Configuring Eclipse for Apache Ant

Problem Context:
Running an Ant build file with a javac kinda task

Error message that appears:
[javac] BUILD FAILED: [build file location here]
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

Solution:

Source:
http://www.dynamicobjects.com/d2r/archives/002591.html

The best solution the author found (after a little bit of digging through Eclipse's options) is to edit Ant's runtime properties. Go to Window > Preferences > Ant > Runtime. Choose the Classpath tab. Select the Global Properties node in the tree and click Add External JARs. Select tools.jar from your JDK directory (e.g., j2sdk1.4.2_03\lib\tools.jar). Click Apply and OK, and you should be on your way. Not too hard when you know what to do. Now if this could only be done automatically by Eclipse on install...

Here is a copy of the original post for reference in case the original link returns an error...

First, the situation. On restart, Eclipse correctly detected the new JRE (clearly from the registry entries created by the JDK/JRE install) to the one the JSDK installs in C:\Program Files\Java\... but it's better to change the pointer to the JRE within the JDK IMO. Even then, Ant doesn't work. The error message you get is for Ant:

[javac] BUILD FAILED: [build file location here]
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

Of course, JAVA_HOME is pointing to the right location, in both the OS environment and within Eclipse (This variable can be set within Eclipse through Window > Preferences > Java > Classpath Variables).

So how to fix the Ant build problem?

I found various solutions searching, for example running Eclipse with "eclipse -vm [JDKPATH]\bin" but that didn't quite satisfy me (I wanted something that could be configured within the environment). Other solutions to the problem where even more esoteric.

The best solution I've found (after a little bit of digging through Eclipse's options) is to edit Ant's runtime properties. Go to Window > Preferences > Ant > Runtime. Choose the Classpath tab. Select the Global Properties node in the tree and click Add External JARs. Select tools.jar from your JDK directory (e.g., j2sdk1.4.2_03\lib\tools.jar). Click Apply and OK, and you should be on your way. Not too hard when you know what to do. Now if this could only be done automatically by Eclipse on install...

Note: Full credit to the original poster.


--Phani