programming

download
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groovy

reference:

[!TIP]Java Tutorial :
Java Exception Handling
Java Tips, How-tos etc
Java JSON Tutorial

basic

get environment

$ groovy -e "println System.getProperty('java.specification.version')"
24

$ groovy -e "println System.getProperties().findAll { it.key.toLowerCase().contains( 'java' ) && it.key != 'sun.java.command' }.collect { \">> \${it.key} -> \${it.value}\" }.join('\n')"
>> java.specification.version -> 24
>> java.runtime.version -> 24.0.1
>> java.class.path -> /opt/groovy/current/lib/groovy-4.0.26.jar
>> java.vm.vendor -> Homebrew
>> java.runtime.name -> OpenJDK Runtime Environment
>> java.vendor.url -> https://github.com/Homebrew/homebrew-core/issues
>> java.vm.specification.version -> 24
>> java.vm.name -> OpenJDK 64-Bit Server VM
>> java.vendor.version -> Homebrew
>> sun.java.launcher -> SUN_STANDARD
>> java.vendor.url.bug -> https://github.com/Homebrew/homebrew-core/issues
>> java.io.tmpdir -> /var/folders/8g/68t3rg090jd2tpqjcwm9vskh0000gq/T/
>> java.version -> 24.0.1
>> java.specification.vendor -> Oracle Corporation
>> java.vm.specification.name -> Java Virtual Machine Specification
>> java.version.date -> 2025-04-15
>> java.home -> /opt/homebrew/Cellar/openjdk/24.0.1/libexec/openjdk.jdk/Contents/Home
>> java.vm.compressedOopsMode -> Zero based
>> java.library.path -> /Users/marslo/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.
>> java.vm.specification.vendor -> Oracle Corporation
>> java.specification.name -> Java Platform API Specification
>> java.vm.info -> mixed mode, sharing
>> java.vendor -> Homebrew
>> java.vm.version -> 24.0.1
>> java.class.version -> 68.0

// sun.java.comman in groovyConsole
println System.getProperty("sun.java.command")
// org.codehaus.groovy.tools.GroovyStarter --main groovy.console.ui.Console --conf /opt/homebrew/opt/groovy/libexec/conf/groovy-starter.conf --classpath .:/opt/homebrew/opt/openjdk/lib/tools.jar:/opt/homebrew/opt/openjdk/lib/dt.jar:/opt/homebrew/opt/groovy/libexec/lib:.

// sun.java.command in cmd
$ groovy -e 'println System.getProperty("sun.java.command")'
// org.codehaus.groovy.tools.GroovyStarter --main groovy.ui.GroovyMain --conf /opt/groovy/current/conf/groovy-starter.conf \ --classpath .:/opt/homebrew/Cellar/openjdk/24.0.1/libexec/openjdk.jdk/Contents/Home/lib/tools.jar:/opt/homebrew/Cellar/openjdk/24.0.1/libexec/openjdk.jdk/Contents/Home/lib/dt.jar:/opt/groovy/current/lib/...jar:/opt/jenkins/latest/WEB-INF/lib/...jar:/opt/jenkins/plugins/credentials/WEB-INF/lib/...jar:. -e println System.getProperty("sun.java.command")

Customizable Operators

Operator

Method

a + b

a.plus(b)

a - b

a.minus(b)

a * b

a.multiply(b)

a / b

a.div(b)

a % b

a.mod(b)

a++ or ++a

a.next()

assert [ a: true, b: false ]  +  [ a: false ] == [ a: false, b: false ]
assert [ a: true, b: false  ] << [ a: false ] == [ a: false, b: false ]
difference +(plus) and <<(left shift) :
<< is to add into left hand map

Special Operators

Operator

Meaning

Name

a ? b : c

if(a) b else c

ternary if

a ?: b

a ? a : b

Elvis

a.?b

( a==null ) ? a : a.b

null safe

a(*list)

a(list[0], list[1], ...)

.& : Method pointer operator

def str = 'example of method reference'
def fun = str.&toUpperCase
assert fun() == str.toUpperCase()
println fun()

// result
EXAMPLE OF METHOD REFERENCE

class Person {
  String name
  Integer age
}
def list = [
  new Person( name: 'Bob'   , age: 42 ) ,
  new Person( name: 'Julia' , age: 35 )
]
String describe(Person p) { "$p.name is $p.age" }

def action = this.&describe
def transform( List<Person> elements, Closure action ) {
  elements.inject([]){ result, e ->
    result << action(e)
    result
  }
}

println transform( list, action )
// result
// [Bob is 42, Julia is 35]

elvis operator

if/elseif{if}/else

references:
5.3. Elvis operator
Groovy Goodness: The Elvis Assignment Operator
usage
?: ( existing Elvis operator )
?= ( new elvis assignment shorthand )

condition:
if fruits is 'apple' or 'orange', get pre-defined number 5 ( number = 5 )
if fruits is watermelon, get particular given numbers. number cannot be null

// by using if/elseif{if}/else
Map option = [:]
if ( [ 'apple', 'orange' ].contains(fruits) ) {
  option = [ "${fruits}" : '5' ]
} else if ( [ 'watermelon' ].contains(fruits) ) {
  if (number) {
    option = [ "${fruits}" : number ]
  }
} else {
  println( 'ERROR: number CANNOT be empty while fruits is watermelon. Exit ...' )
}

// by using elvis operator
Map option = ( [ 'apple', 'orange' ].contains(fruits) ) ? [ "${fruits}" : '5' ]
           : ( [ 'watermelon' ].contains(fruits) ) ? ( number )
              ? [ "${fruits}" : number ]
              : println( 'ERROR: number CANNOT be empty while fruits is watermelon. Exit ...' )
           : [:]

example

Closure option = { String fruits, String number = '' ->
    ( [ 'apple', 'orange' ].contains(fruits) ) ? [ (fruits) : '5' ]
    : ( [ 'watermelon' ].contains(fruits) ) ? ( number )
      ? [ (fruits) : number ]
      : println( 'ERROR: number CANNOT be empty while fruits is watermelon. Exit ...' )
    : [:]
}

assert option('apple') == ['apple' : '5']
assert option('watermelon', '100') == [ 'watermelon' : '100' ]

using [ "${fruits}" : '5' ], the class of key is class org.codehaus.groovy.runtime.GStringImpl
using [ (fruits) : '5' ] , the class of key is class java.lang.String

execute shell commands in groovy

reference
101 groovy script - Execute commands
Jenkins Groovy script to execute shell commands

Get STDERR & STDERR

[!TIP] using new StringBuffer() or new StringBuilder()

i.e.:

def stdout = new StringBuffer(), stderr = new StringBuffer()
def proc = "cmd".execute()
proc.waitForProcessOutput( stdout, stderr )
int exitCode = proc.exitValue()
println( (exitCode == 0) ? stdout : "exit with ${exitCode}. error: ${stderr}" )

def stdout = new StringBuilder(), stderr = new StringBuilder()

def proc = "ls /tmp/NoFile".execute()
proc.consumeProcessOutput( stdout, stderr )
proc.waitForOrKill( 1000 )

int exitCode = proc.exitValue()
println( ( exitCode == 0 ) ? stdout : "error with exit code ${exitCode}.\nSTDERR: ${stderr}" )

def stdout = new StringBuilder(), stderr = new StringBuilder()
def proc = 'ls /tmp/NoFile'.execute()
proc.consumeProcesstdoutput( stdout, stderr )
proc.waitForOrKill(1000)
println( stdout ? "out> \n${stdout}" : '' + stderr ? "err> \n${stderr}" : '' )

Show output during the process

using System.out and System.err

def proc = "ls /tmp/NoFile".execute()
proc.waitForProcessOutput( System.out, System.err )
proc.waitForOrKill(1000)

int exitCode = proc.exitValue()
if ( exitCode != 0 ) {
  println "error with exit code ${exitCode}."
}

with environment

def envVars = ["GROOVY_HOME=/fake/path/groovy-3.0.7", "CLASSPATH=.:/fake/path/groovy-3.0.7/lib"]

def proc = './run.sh'.execute( envVars, new File(".") )
proc.waitForProcessOutput( System.out, System.err )
int exitCode = proc.exitValue()

println( (exitCode != 0) ? "exit with ${exitCode}" : '' )

run.sh
```
env
echo ${GROOVY_HOME}
```
result

with system environment

List envVars = System.getenv().collect { k, v -> "${k}=${v}" }

def proc = "./run.sh".execute( envVars, new File(".") )
proc.waitForProcessOutput( System.out, System.err )
int exitCode = proc.exitValue()

println( (exitCode != 0) ? "exit with ${exitCode}" : '' )

with partular path

reference:
groovy execute shell with environment and working dir

def command = "git log -1"
def proc = command.execute( null, new File('/path/to/folder') )
proc.waitFor()

println """
  ${proc.err.text ?: ''}
  ${proc.in.text ?: ''}
  Process exit code: ${proc.exitValue()}
"""

groovyConsole

environment

[!NOTE]
System.setProperty("file.encoding","UTF-8")
font setup for groovyConsole
Groovy console

> setx JAVA_OPT '-Dfile.encoding=UTF-8 -Dsun.jnu.encoding=UTF-8'
> setx GROOVY_OPT '-Dfile.encoding=UTF-8'
> setx JAVA_TOOL_OPTIONS '-Dfile.encoding=UTF-8'

get console details

charset

import java.nio.charset.Charset

System.out.println( String.format("file.encoding: %s", System.getProperty("file.encoding")) );
System.out.println( String.format("defaultCharset: %s", Charset.defaultCharset().name()) );

result

file.encoding: UTF-8
defaultCharset: UTF-8

font

[!NOTE|label:references:]
GROOVY-6303: Add ability to use a different font for the input/output area of Groovy Console
windows : add font/Name into HKEY_CURRENT_USER\SOFTWARE\JavaSoft\Prefs\groovy\console\ui
> REG ADD "HKCU\SOFTWARE\JavaSoft\Prefs\groovy\console\ui" /v "font/Name" /t REG_SZ /d "Monaco" /f
linux : add fontName into ~/.java/.userPrefs/groovy/ui/prefs.xml
macox : add fontName into ~/Library/Preferences/com.apple.java.JavaPreferences.plist

check font

javax.swing.UIManager.getLookAndFeelDefaults()

// or
javax.swing.UIManager.getLookAndFeelDefaults().each {
  println "... ${it.key} : ${it.value}"
}

import java.awt.Font
for (Map.Entry<Object, Object> entry : javax.swing.UIManager.getDefaults().entrySet()) {
    Object key = entry.getKey();
    Object value = javax.swing.UIManager.get(key);
    if (value != null && value instanceof javax.swing.plaf.FontUIResource) {
      println ".. ${key} : ${value}"
    }
}

.. FormattedTextField.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. MenuItem.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. InternalFrame.titleFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. RadioButton.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. RadioButton.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. OptionPane.buttonFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ToolTip.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. FormattedTextField.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Panel.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. RadioButtonMenuItem.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. OptionPane.messageFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. PopupMenu.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. CheckBoxMenuItem.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. MenuItem.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. CheckBoxMenuItem.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. RadioButtonMenuItem.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. RadioButtonMenuItem.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TabbedPane.smallFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Panel.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. OptionPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. EditorPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Label.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ComboBox.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Button.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. MenuBar.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Tree.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Tree.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ToolBar.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Button.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ComboBox.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Label.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. EditorPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Menu.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TextArea.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TextField.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Spinner.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. CheckBoxMenuItem.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Spinner.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TextField.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. IconButton.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. InternalFrame.titleFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. OptionPane.messageFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Menu.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Menu.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ToolBar.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TitledBorder.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Menu.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. FileChooser.listFont : javax.swing.plaf.FontUIResource[family=Segoe UI,name=Segoe UI,style=plain,size=12]
.. ToolTip.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TitledBorder.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. OptionPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. MenuBar.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TextArea.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. OptionPane.buttonFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. CheckBoxMenuItem.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. InternalFrame.optionDialogTitleFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. InternalFrame.paletteTitleFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Table.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. CheckBox.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. List.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ToggleButton.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ScrollPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ScrollPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ToggleButton.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. List.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ColorChooser.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. CheckBox.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ColorChooser.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Table.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. MenuItem.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TableHeader.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TextPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Viewport.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ProgressBar.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. PasswordField.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TabbedPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Slider.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Slider.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TabbedPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. RadioButtonMenuItem.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. PasswordField.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. ProgressBar.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TableHeader.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. TextPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. MenuItem.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. Viewport.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]
.. PopupMenu.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]

modify font

import javax.swing.plaf.FontUIResource
import javax.swing.UIManager
import java.awt.Font

UIManager.put("Panel.font", new FontUIResource(new Font ("Monaco", Font.PLAIN, 16)));

other options

[!NOTE|label:references:]
Swing UIManager Keys

private void setFont(FontUIResource myFont) {
    UIManager.put("CheckBoxMenuItem.acceleratorFont", myFont);
    UIManager.put("Button.font", myFont);
    UIManager.put("ToggleButton.font", myFont);
    UIManager.put("RadioButton.font", myFont);
    UIManager.put("CheckBox.font", myFont);
    UIManager.put("ColorChooser.font", myFont);
    UIManager.put("ComboBox.font", myFont);
    UIManager.put("Label.font", myFont);
    UIManager.put("List.font", myFont);
    UIManager.put("MenuBar.font", myFont);
    UIManager.put("Menu.acceleratorFont", myFont);
    UIManager.put("RadioButtonMenuItem.acceleratorFont", myFont);
    UIManager.put("MenuItem.acceleratorFont", myFont);
    UIManager.put("MenuItem.font", myFont);
    UIManager.put("RadioButtonMenuItem.font", myFont);
    UIManager.put("CheckBoxMenuItem.font", myFont);
    UIManager.put("OptionPane.buttonFont", myFont);
    UIManager.put("OptionPane.messageFont", myFont);
    UIManager.put("Menu.font", myFont);
    UIManager.put("PopupMenu.font", myFont);
    UIManager.put("OptionPane.font", myFont);
    UIManager.put("Panel.font", myFont);
    UIManager.put("ProgressBar.font", myFont);
    UIManager.put("ScrollPane.font", myFont);
    UIManager.put("Viewport.font", myFont);
    UIManager.put("TabbedPane.font", myFont);
    UIManager.put("Slider.font", myFont);
    UIManager.put("Table.font", myFont);
    UIManager.put("TableHeader.font", myFont);
    UIManager.put("TextField.font", myFont);
    UIManager.put("Spinner.font", myFont);
    UIManager.put("PasswordField.font", myFont);
    UIManager.put("TextArea.font", myFont);
    UIManager.put("TextPane.font", myFont);
    UIManager.put("EditorPane.font", myFont);
    UIManager.put("TabbedPane.smallFont", myFont);
    UIManager.put("TitledBorder.font", myFont);
    UIManager.put("ToolBar.font", myFont);
    UIManager.put("ToolTip.font", myFont);
    UIManager.put("Tree.font", myFont);
    UIManager.put("FormattedTextField.font", myFont);
    UIManager.put("IconButton.font", myFont);
    UIManager.put("InternalFrame.optionDialogTitleFont", myFont);
    UIManager.put("InternalFrame.paletteTitleFont", myFont);
    UIManager.put("InternalFrame.titleFont", myFont);
}
setFont(new FontUIResource(new Font("Monaco", Font.PLAIN, 14)));

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$ groovy -e "println System.getProperties().findAll { it.key.toLowerCase().contains( 'java' ) && it.key != 'sun.java.command' }.collect { \">> \${it.key} -> \${it.value}\" }.join('\n')" >> java.specification.version -> 24 >> java.runtime.version -> 24.0.1 >> java.class.path -> /opt/groovy/current/lib/groovy-4.0.26.jar >> java.vm.vendor -> Homebrew >> java.runtime.name -> OpenJDK Runtime Environment >> java.vendor.url -> https://github.com/Homebrew/homebrew-core/issues >> java.vm.specification.version -> 24 >> java.vm.name -> OpenJDK 64-Bit Server VM >> java.vendor.version -> Homebrew >> sun.java.launcher -> SUN_STANDARD >> java.vendor.url.bug -> https://github.com/Homebrew/homebrew-core/issues >> java.io.tmpdir -> /var/folders/8g/68t3rg090jd2tpqjcwm9vskh0000gq/T/ >> java.version -> 24.0.1 >> java.specification.vendor -> Oracle Corporation >> java.vm.specification.name -> Java Virtual Machine Specification >> java.version.date -> 2025-04-15 >> java.home -> /opt/homebrew/Cellar/openjdk/24.0.1/libexec/openjdk.jdk/Contents/Home >> java.vm.compressedOopsMode -> Zero based >> java.library.path -> /Users/marslo/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:. >> java.vm.specification.vendor -> Oracle Corporation >> java.specification.name -> Java Platform API Specification >> java.vm.info -> mixed mode, sharing >> java.vendor -> Homebrew >> java.vm.version -> 24.0.1 >> java.class.version -> 68.0

// sun.java.comman in groovyConsole println System.getProperty("sun.java.command") // org.codehaus.groovy.tools.GroovyStarter --main groovy.console.ui.Console --conf /opt/homebrew/opt/groovy/libexec/conf/groovy-starter.conf --classpath .:/opt/homebrew/opt/openjdk/lib/tools.jar:/opt/homebrew/opt/openjdk/lib/dt.jar:/opt/homebrew/opt/groovy/libexec/lib:. // sun.java.command in cmd $ groovy -e 'println System.getProperty("sun.java.command")' // org.codehaus.groovy.tools.GroovyStarter --main groovy.ui.GroovyMain --conf /opt/groovy/current/conf/groovy-starter.conf \ --classpath .:/opt/homebrew/Cellar/openjdk/24.0.1/libexec/openjdk.jdk/Contents/Home/lib/tools.jar:/opt/homebrew/Cellar/openjdk/24.0.1/libexec/openjdk.jdk/Contents/Home/lib/dt.jar:/opt/groovy/current/lib/...jar:/opt/jenkins/latest/WEB-INF/lib/...jar:/opt/jenkins/plugins/credentials/WEB-INF/lib/...jar:. -e println System.getProperty("sun.java.command")

class Person { String name Integer age } def list = [ new Person( name: 'Bob' , age: 42 ) , new Person( name: 'Julia' , age: 35 ) ] String describe(Person p) { "$p.name is $p.age" } def action = this.&describe def transform( List<Person> elements, Closure action ) { elements.inject([]){ result, e -> result << action(e) result } } println transform( list, action ) // result // [Bob is 42, Julia is 35]

// by using if/elseif{if}/else Map option = [:] if ( [ 'apple', 'orange' ].contains(fruits) ) { option = [ "${fruits}" : '5' ] } else if ( [ 'watermelon' ].contains(fruits) ) { if (number) { option = [ "${fruits}" : number ] } } else { println( 'ERROR: number CANNOT be empty while fruits is watermelon. Exit ...' ) } // by using elvis operator Map option = ( [ 'apple', 'orange' ].contains(fruits) ) ? [ "${fruits}" : '5' ] : ( [ 'watermelon' ].contains(fruits) ) ? ( number ) ? [ "${fruits}" : number ] : println( 'ERROR: number CANNOT be empty while fruits is watermelon. Exit ...' ) : [:]

Closure option = { String fruits, String number = '' -> ( [ 'apple', 'orange' ].contains(fruits) ) ? [ (fruits) : '5' ] : ( [ 'watermelon' ].contains(fruits) ) ? ( number ) ? [ (fruits) : number ] : println( 'ERROR: number CANNOT be empty while fruits is watermelon. Exit ...' ) : [:] } assert option('apple') == ['apple' : '5'] assert option('watermelon', '100') == [ 'watermelon' : '100' ]

def stdout = new StringBuffer(), stderr = new StringBuffer() def proc = "cmd".execute() proc.waitForProcessOutput( stdout, stderr ) int exitCode = proc.exitValue() println( (exitCode == 0) ? stdout : "exit with ${exitCode}. error: ${stderr}" )

def stdout = new StringBuilder(), stderr = new StringBuilder() def proc = "ls /tmp/NoFile".execute() proc.consumeProcessOutput( stdout, stderr ) proc.waitForOrKill( 1000 ) int exitCode = proc.exitValue() println( ( exitCode == 0 ) ? stdout : "error with exit code ${exitCode}.\nSTDERR: ${stderr}" )

def stdout = new StringBuilder(), stderr = new StringBuilder() def proc = 'ls /tmp/NoFile'.execute() proc.consumeProcesstdoutput( stdout, stderr ) proc.waitForOrKill(1000) println( stdout ? "out> \n${stdout}" : '' + stderr ? "err> \n${stderr}" : '' )

def proc = "ls /tmp/NoFile".execute() proc.waitForProcessOutput( System.out, System.err ) proc.waitForOrKill(1000) int exitCode = proc.exitValue() if ( exitCode != 0 ) { println "error with exit code ${exitCode}." }

def envVars = ["GROOVY_HOME=/fake/path/groovy-3.0.7", "CLASSPATH=.:/fake/path/groovy-3.0.7/lib"] def proc = './run.sh'.execute( envVars, new File(".") ) proc.waitForProcessOutput( System.out, System.err ) int exitCode = proc.exitValue() println( (exitCode != 0) ? "exit with ${exitCode}" : '' )

List envVars = System.getenv().collect { k, v -> "${k}=${v}" } def proc = "./run.sh".execute( envVars, new File(".") ) proc.waitForProcessOutput( System.out, System.err ) int exitCode = proc.exitValue() println( (exitCode != 0) ? "exit with ${exitCode}" : '' )

def command = "git log -1" def proc = command.execute( null, new File('/path/to/folder') ) proc.waitFor() println """ ${proc.err.text ?: ''} ${proc.in.text ?: ''} Process exit code: ${proc.exitValue()} """

import java.nio.charset.Charset System.out.println( String.format("file.encoding: %s", System.getProperty("file.encoding")) ); System.out.println( String.format("defaultCharset: %s", Charset.defaultCharset().name()) );

import java.awt.Font for (Map.Entry<Object, Object> entry : javax.swing.UIManager.getDefaults().entrySet()) { Object key = entry.getKey(); Object value = javax.swing.UIManager.get(key); if (value != null && value instanceof javax.swing.plaf.FontUIResource) { println ".. ${key} : ${value}" } }

.. FormattedTextField.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. MenuItem.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. InternalFrame.titleFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. RadioButton.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. RadioButton.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. OptionPane.buttonFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ToolTip.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. FormattedTextField.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Panel.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. RadioButtonMenuItem.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. OptionPane.messageFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. PopupMenu.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. CheckBoxMenuItem.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. MenuItem.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. CheckBoxMenuItem.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. RadioButtonMenuItem.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. RadioButtonMenuItem.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TabbedPane.smallFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Panel.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. OptionPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. EditorPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Label.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ComboBox.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Button.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. MenuBar.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Tree.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Tree.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ToolBar.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Button.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ComboBox.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Label.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. EditorPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Menu.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TextArea.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TextField.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Spinner.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. CheckBoxMenuItem.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Spinner.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TextField.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. IconButton.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. InternalFrame.titleFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. OptionPane.messageFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Menu.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Menu.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ToolBar.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TitledBorder.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Menu.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. FileChooser.listFont : javax.swing.plaf.FontUIResource[family=Segoe UI,name=Segoe UI,style=plain,size=12] .. ToolTip.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TitledBorder.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. OptionPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. MenuBar.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TextArea.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. OptionPane.buttonFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. CheckBoxMenuItem.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. InternalFrame.optionDialogTitleFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. InternalFrame.paletteTitleFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Table.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. CheckBox.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. List.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ToggleButton.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ScrollPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ScrollPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ToggleButton.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. List.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ColorChooser.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. CheckBox.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ColorChooser.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Table.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. MenuItem.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TableHeader.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TextPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Viewport.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ProgressBar.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. PasswordField.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TabbedPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Slider.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Slider.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TabbedPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. RadioButtonMenuItem.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. PasswordField.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. ProgressBar.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TableHeader.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. TextPane.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. MenuItem.acceleratorFont : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. Viewport.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14] .. PopupMenu.font : javax.swing.plaf.FontUIResource[family=Dialog,name=Monaco,style=plain,size=14]

private void setFont(FontUIResource myFont) { UIManager.put("CheckBoxMenuItem.acceleratorFont", myFont); UIManager.put("Button.font", myFont); UIManager.put("ToggleButton.font", myFont); UIManager.put("RadioButton.font", myFont); UIManager.put("CheckBox.font", myFont); UIManager.put("ColorChooser.font", myFont); UIManager.put("ComboBox.font", myFont); UIManager.put("Label.font", myFont); UIManager.put("List.font", myFont); UIManager.put("MenuBar.font", myFont); UIManager.put("Menu.acceleratorFont", myFont); UIManager.put("RadioButtonMenuItem.acceleratorFont", myFont); UIManager.put("MenuItem.acceleratorFont", myFont); UIManager.put("MenuItem.font", myFont); UIManager.put("RadioButtonMenuItem.font", myFont); UIManager.put("CheckBoxMenuItem.font", myFont); UIManager.put("OptionPane.buttonFont", myFont); UIManager.put("OptionPane.messageFont", myFont); UIManager.put("Menu.font", myFont); UIManager.put("PopupMenu.font", myFont); UIManager.put("OptionPane.font", myFont); UIManager.put("Panel.font", myFont); UIManager.put("ProgressBar.font", myFont); UIManager.put("ScrollPane.font", myFont); UIManager.put("Viewport.font", myFont); UIManager.put("TabbedPane.font", myFont); UIManager.put("Slider.font", myFont); UIManager.put("Table.font", myFont); UIManager.put("TableHeader.font", myFont); UIManager.put("TextField.font", myFont); UIManager.put("Spinner.font", myFont); UIManager.put("PasswordField.font", myFont); UIManager.put("TextArea.font", myFont); UIManager.put("TextPane.font", myFont); UIManager.put("EditorPane.font", myFont); UIManager.put("TabbedPane.smallFont", myFont); UIManager.put("TitledBorder.font", myFont); UIManager.put("ToolBar.font", myFont); UIManager.put("ToolTip.font", myFont); UIManager.put("Tree.font", myFont); UIManager.put("FormattedTextField.font", myFont); UIManager.put("IconButton.font", myFont); UIManager.put("InternalFrame.optionDialogTitleFont", myFont); UIManager.put("InternalFrame.paletteTitleFont", myFont); UIManager.put("InternalFrame.titleFont", myFont); } setFont(new FontUIResource(new Font("Monaco", Font.PLAIN, 14)));

programming

basic

get environment

Program structure

Customizable Operators

Special Operators

elvis operator

if/elseif{if}/else

execute shell commands in groovy

Get STDERR & STDERR

Show output during the process

with environment

groovyConsole

environment

get console details

font

basic

get environment

Program structure

Customizable Operators

Special Operators

elvis operator

if/elseif{if}/else

execute shell commands in groovy

Get STDERR & STDERR

Show output during the process

with environment

groovyConsole

environment

get console details

font