Setting the classpath to a string which is in a txt file

Question

I am trying to run the JUnit Test program through the command line from Java application. In java file, I am using the following commands,

Runtime rt = Runtime.getRuntime();
Process pr = rt.exec("java -jar map.jar time.rel test.txt debug");

In the exec function, I am adding the following command to run the Junit,

java -cp cp.txt org.junit.runner.JUnitCore Testing

In place of cp.txt, I gave the classpath which is very long and this approach throws me the following error,

Cannot run program "java": CreateProcess error=206, The filename or extension is too long

So I want to place the string in cp.txt and give it as classpath in the command. Any help would be greatly appreciated. TIA

Just put the CLASSPATH into the JAR file and use `java -jar` as you were originally doing. — user207421, May 30 '18 at 11:56
@EJP what does that mean putting the classpath into the jar file, can you please elaborate? — harry, May 30 '18 at 13:27
@Antoniossss yeah, I heard of it. Do u want me to add an entry in that? — harry, May 31 '18 at 08:36

score 0 · Answer 1 · answered May 30 '18 at 11:44

You can achieve this by just storing the content of your text file to a variable and then use this as your class path. If your using e.g. bash you can simple do that in a one-liner:

java -cp $(cat cp.txt) org.junit.runner.JUnitCore Testing

If your text file contains newline, you could even simply replace them with ; like this:

java -cp $(cat cp.txt | tr '\n' ';') org.junit.runner.JUnitCore Testing

I'm pretty sure you can do this on Windows too, but there the syntax is probably slightly different. This post should help you there.

Even for a variable, there is a limit, so unable to store the entire classpath in the variable. — harry, May 30 '18 at 13:25

Setting the classpath to a string which is in a txt file

1 Answers1