Facing NoClassDefFoundError despite jar being in classpath (dynamic compilation) #31

In a tomcat server, at run time, I am reading java class files and compiling them dynamically using InMemoryJavaCompiler.
Code Sample -

InMemoryJavaCompiler.newInstance()
                       .useOptions("-parameters", 
                          "-classpath", sb.toString(),  
                          "-Xlint:unchecked")
                       .compile(sourceCodeClassName,
                          sourceCode.toString());

Here sb (Stringbuilder) indicates the jars read from WEB-INF/lib directory separated by a colon.
The code works in the following scenarios :
1. If the above compilation code is kept in a standalone class file & the relevant libraries are set in the classpath, the compilation from a bash script was successful.
2. I printed the jar files i.e. I printed sb value separately & took a copy of it. I manually ran javac -classpath <sourceCode.java> in the terminal. The compilation was successful.

The code is not working in the following scenarios :

a. When the above code snippet is added as a stand alone program in IDE(Eclipse), I faced NoClassDefFound error for the interface which the sourceCode was implementing.

b. In Tomcat, the relevant jar is present in contextName/WEB-INF/lib/ and in addition to that the jar is added in -useOptions classpath. Even then, I am facing NoClassDefFound error for the the interface the sourceCode was implementing.

Note : There are no duplicate copies of the jar or multiple versions of the jar present in the lib directory or the classpath value.