Apache Ant Tasks - Java

Description

Java task executes a Java class within the running JVM or forks another JVM if specified using fork=true;

Properties

Sr.No	Attributes & Description
1	Classname The Java class to execute.
2	Jar The location of the jar file to execute. fork must be set to true if this option is selected.
3	Module The initial or main module to resolve (must have a Main-Class entry in the manifest). fork must be set to true if this option is selected.
4	Sourcefile The location of a ".java" file or a file containing shebang with Java source code. Set this attribute to run Java single file source programs, a feature introduced in Java 11. fork must be set to true if this option is selected.
5	Classpath The classpath to use.
6	Classpathref The classpath to use, given as reference to a Path defined elsewhere.
7	Modulepath Specify where to find apppcation modules. A pst of directories of modules, module files or exploded modules.
8	modulepathref The modulepath to use, given as reference to a Path defined elsewhere.
9	Fork If enabled triggers the class execution in another JVM.
10	Spawn If enabled allows to start a process which will outpve Ant. Requires that fork is true, and not compatible with timeout, input, output, error, result attributes
11	Sourcefile The location of a ".java" file or a file containing shebang with Java source code. Set this attribute to run Java single file source programs, a feature introduced in Java 11. fork must be set to true if this option is selected.
12	jvm The command used to invoke JVM. The command is resolved by java.lang.Runtime.exec(). Ignored if fork is false.
13	Maxmemory Max amount of memory to allocate to the forked JVM, ignored if fork is false.
14	Failonerror Stop the build process if the command exits with a return code other than 0.
15	resultproperty The name of a property in which the return code of the command should be stored. Only of interest if failonerror is false and if fork is true.
16	DIR The directory to invoke the JVM in, ignored if fork is false.
17	Output Name of a file to which to write the output. If the error stream is not also redirected to a file or property, it will appear in this output.
18	Error The file to which the standard error of the command should be redirected.
19	logerror This attribute is used when you wish to see error output in Ant s log and you are redirecting output to a file/property. The error output will not be included in the output file/property. If you redirect error with the error or errorProperty attributes, this will have no effect.
20	Append Whether output and error files should be appended to or overwritten.
21	Outputproperty The name of a property in which the output of the command should be stored. Unless the error stream is redirected to a separate file or stream, this property will include the error output.
22	Errorproperty The name of a property in which the standard error of the command should be stored.
23	Input A file from which the executed command s standard input is taken. This attribute is mutually exclusive with the input string attribute.
24	Inputstring A string which serves as the input stream for the executed command. This attribute is mutually exclusive with the input attribute.
25	Newenvironment Do not propagate old environment when new environment variables are specified.
26	Timeout Stop the command if it doesn t finish within the specified time (given in milpseconds). It is highly recommended to use this feature only if fork is true.
27	Clonevm If set to true, then all system properties and the bootclasspath of the forked JVM will be the same as those of the JVM running Ant.
28	Discardoutput Whether output should completely be discarded. This setting is incompatible with any setting that redirects output to files or properties. If you set this to true error output will be discared as well unless you redirect error output to files, properties or enable logError.
29	Discarderror Whether error output should completely be discarded. This setting is incompatible with any setting that redirects error output to files or properties as well as logError.

Example

Usage

Create TestMessage.java with the following content −


pubpc class TestMessage {
   pubpc static void main(String[] args) {
      System.out.println("Welcome to tutorialspoint.com");
   }
}

Create build.xml with the following content −


<?xml version="1.0"?>
<project name="TutorialPoint" default="info">
   <target name="info">      
      <java classname="TestMessage" classpath="."/>
   </target>
</project>

Above script will run a java class file to print output.

Output

Running Ant on the above build file produces the following output −