Java "constant string too long" compile error. Only happens using Ant, not when using Eclipse

Question

I have a few really long strings in one class for initializing user information. When I compile in Eclipse, I don't get any errors or warnings, and the resulting .jar runs fine.

Recently, I decided to create an ant build file to use. Whenever I compile the same class with ant, I get the "constant string too long" compile error. I've tried a number of ways to set the java compiler executable in ant to make sure that I'm using the exact same version as in Eclipse.

I'd rather figure out how to get the same successful compile I get in Eclipse in Ant than try to rework the code to dynamically concatenate the strings.

Answer 1

Someone is trying to send you a message :-) In the time you've spend fiddling with compiler versions you could have loaded the data from a text file - which is probably where it belongs.

Check out:

• java.util.Properties
• Apache Commons FileUtils.readStringFromFile()

Answer 2

Did you try this? Never tried it myself, but here is the relevant section:

Using the ant javac adapter The Eclipse compiler can be used inside an Ant script using the javac adapter. In order to use the Eclipse compiler, you simply need to define the build.compiler property in your script. Here is a small example.

 <?xml version="1.0" encoding="UTF-8"?>
 <project name="compile" default="main" basedir="../.">

<property name="build.compiler" value="org.eclipse.jdt.core.JDTCompilerAdapter"/>

<property name="root" value="${basedir}/src"/>

<property name="destdir" value="d:/temp/bin" />

<target name="main">
    <javac srcdir="${root}" destdir="${destdir}" debug="on" nowarn="on" extdirs="d:/extdirs" source="1.4">
        <classpath>
          <pathelement location="${basedir}/../org.eclipse.jdt.core/bin"/>
        </classpath>
    </javac>        
</target>
</project>

I would really consider making your classes standards compatible. I believe the official limit is 65535, and the fact that Eclipse is more lenient is something that could change on you at the most inconvenient of times, and either way constantly having to get the project compiled with Eclipse can really start to limit you in too many ways.

Answer 3

The length of a string constant in a class file is limited to 2^16 bytes in UTF-8 encoding, this should not be dependent on the compiler used. Perhaps you are using a different character set in your ant file than in eclipse, so that some characters need more bytes than before. Please check the encoding attribute of your javac task.