以编程方式构建Netbeans平台应用程序时Ant类路径错误

Question

I want to run a Netbeans 7.3 platform application (let's name it app A) from another Java application (app B). To do this, in B's code I'm invoking the Ant library as follows:

Path pathA = ... // where the A's sources are
Path fileBuild = pathA.resolve("build.xml");
Project p = new Project();
p.setUserProperty("ant.file", fileBuild.toFile().getAbsolutePath());
p.init();
ProjectHelper helper = ProjectHelper.getProjectHelper();
p.addReference("ant.projectHelper", helper);
helper.parse(p, buildFile);
p.setDefault("run");
p.executeTarget(p.getDefaultTarget());

Unfortunately, the error I'm getting is:

C:\Program Files\NetBeans 7.3\harness\suite.xml:184: The following error occurred while executing this line:
C:\Program Files\NetBeans 7.3\harness\common.xml:217: Unable to find a javac compiler;
com.sun.tools.javac.Main is not on the classpath.
Perhaps JAVA_HOME does not point to the JDK.
It is currently set to "C:\Program Files (x86)\Java\jdk1.7.0_45\jre"
    at org.apache.tools.ant.ProjectHelper.addLocationToBuildException(ProjectHelper.java:568)
    at org.apache.tools.ant.taskdefs.Ant.execute(Ant.java:443)
    at org.apache.tools.ant.taskdefs.SubAnt.execute(SubAnt.java:306)
    at org.apache.tools.ant.taskdefs.SubAnt.execute(SubAnt.java:221)
    at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:292)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
    at org.apache.tools.ant.Task.perform(Task.java:348)
    at org.apache.tools.ant.Target.execute(Target.java:435)
    at org.apache.tools.ant.Target.performTasks(Target.java:456)
    at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1393)
    at org.apache.tools.ant.Project.executeTarget(Project.java:1364)
...

The JAVA_HOME variable is set correctly both as system path variable and in netbeans config file and points to C:\\Program Files (x86)\\Java\\jdk1.7.0_45 .

The question is, what am I missing? When running the app A from Netbeans menu, everything runs fine, so what should I append to the build file/ant settings to achieve A runs from B's code execution?

Thanks in advance!

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Edit: I managed to get a more precise error stack, maybe this can help.

Error on test cases execution.
C:\Program Files\NetBeans 7.3\harness\common.xml:217: Unable to find a javac compiler;
com.sun.tools.javac.Main is not on the classpath.
Perhaps JAVA_HOME does not point to the JDK.
It is currently set to "C:\Program Files (x86)\Java\jdk1.7.0_45\jre"
    at org.apache.tools.ant.taskdefs.compilers.CompilerAdapterFactory.getCompiler(CompilerAdapterFactory.java:130)
    at org.apache.tools.ant.taskdefs.Javac.findSupportedFileExtensions(Javac.java:984)
    at org.apache.tools.ant.taskdefs.Javac.scanDir(Javac.java:961)
    at org.apache.tools.ant.taskdefs.Javac.execute(Javac.java:932)
    at org.netbeans.nbbuild.CustomJavac.execute(CustomJavac.java:105)
    at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:292)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
    at org.apache.tools.ant.Task.perform(Task.java:348)
    at org.apache.tools.ant.Target.execute(Target.java:435)
    at org.apache.tools.ant.Target.performTasks(Target.java:456)
    at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1393)
    at org.apache.tools.ant.Project.executeTarget(Project.java:1364)
    at odoetest.server.ServerInvokerAnt.start(ServerInvokerAnt.java:48)
    at odoetest.EntryPoint.invokeTests(EntryPoint.java:58)
    at odoetest.EntryPoint.main(EntryPoint.java:38)

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Edit-2: I don't have any separate ant installation and use the ant delivered with Netbeans. When I run ant -diagnostics , I get this info . When I invoke the build or run job from the command line like

ant -f /path/to/build.xml run

no errors are thrown, the program starts. I just can't do the exact same thing from java code from above.

Answer 1

Your Ant build.xml will still be referring to a JRE rather than the JDK.

Right-click on your project, select Libraries , check that Java Platform points to a JDK rather than a JRE. See here for details.

If this fails:

You can explicitly set properties for Project p as in manouti's answer above. This will ensure that Project p as well as Project A will be referring to a JDK rather than JRE. AFAIK, no need to fork.

You can set properties in your .properties file, though it is not always easy to debug whether this is being implemented for each project.

You can explicitly include folders/files on the classpath of your target using the <classpath> element - see the Apache Ant Manual for some not very clear documentation.

This would be:

<classpath>
  <pathelement path="${path.to.jdk}"/>
</classpath>

See also this answer .

Answer 2

NetBeans has setting which java to use internally. It's part of the netbeans.conf file. You are able to set the Java version for every NetBeans project which might be different.

However your JAVA_HOME points to a JRE and not JDK. That's why it cannot find the compiler - javac .

Answer 3

The error is occurring when calling the Ant javac task. Try to locate the call to that task (it should be in common.xml at the line shown in the error message), and try adding fork="yes" to it so that it runs the JDK compiler in an external process. See http://ant.apache.org/manual/Tasks/javac.html :

<javac fork="yes" ...

Also try adding the following property in the project invocation:

Project p = new Project();
p.setUserProperty("ant.file", fileBuild.toFile().getAbsolutePath());
p.setProperty("java.home", "C:\\Program Files (x86)\\Java\\jdk1.7.0_45");