Ant is using wrong java version

Question

Just had this issue, it happened because I'd first added the build file to the ant-view when the default JRE was 1.6.

There was no project-specific JRE and I changed the default to 1.5, even eclipse was running in 1.5, and JAVA_HOME was 1.5 too. Running the ant target from the command line used JRE 1.5, but within eclipse it still used 1.6.

I had to right-click the ant target, select Run As... and change the JRE under the JRE tab. This setting is remembered for subsequent runs.

In Eclipse:

• Right click on your build.xml

• click "Run As", click on "External Tool Configurations..."

• Select tab JRE. Select the JRE you are using.

Re-run the task, it should be fine now.

According to the ant manual, setting JAVA_HOME should work - are you sure the changed setting is visible to ant?

Alternatively, you could use the JAVACMD variable.

Run ant in verbose mode : ant -v and looks for clues.

You can use the target and source properties on the javac tag to set a target runtime. The example below will compile any source code to target version 1.4 on any compiler that supports version 1.4 or later.

<javac compiler="classic" taskname="javac" includeAntRuntime="no" fork=" deprecation="true" target="1.4" source="1.4" srcdir="${src}" destdir="${classes}">

Note: The 'srcdir' and 'destdir' are property values set else where in the build script, e.g. <property name="classes" value="c:/classes" />