Just compiled and installed gcc-4.3.0. Getting java.lang.NoClassDefFoundError while compiling a test program. The class that's not found (org.eclipse.jdt.internal.compiler.batch.GCCMain) is in ecj.jar listed in the bootclasspath. Help is greatly appreciated. Thanks Gopi # gcj -v Test.java Using built-in specs. Reading specs from /root/gcc-4.3.0-install/usr/local/lib/libgcj.spec rename spec startfile to startfileorig rename spec lib to liborig Target: i686-pc-linux-gnu Configured with: ../gcc-4.3.0/configure Thread model: posix gcc version 4.3.0 (GCC) COLLECT_GCC_OPTIONS='-fsaw-java-file' '-v' '-fbootclasspath=/root/gcc-4.3.0/ecj.jar:/root/gcc-4.3.0-install/usr/loc al/bin/../lib/gcc/../../share/java/libgcj-4.3.0.jar' '-g1' '-shared-libgcc' '-mtune=generic' /root/gcc-4.3.0-install/usr/local/bin/../libexec/gcc/i686-pc-linux-gnu/4 .3.0/ecj1 Test.java -g1 -fbootclasspath=/root/gcc-4.3.0/ecj.jar:/root/gcc-4.3.0-install/usr/loca l/bin/../lib/gcc/../../share/java/libgcj-4.3.0.jar -g1 -fsource=1.5 -ftarget=1.5 -fzip-dependency /tmp/cczzFftb.zip -fzip-target /tmp/cc8J4uMc.jar Exception in thread "main" java.lang.NoClassDefFoundError: org.eclipse.jdt.internal.compiler.batch.GCCMain at gnu.java.lang.MainThread.run(MainThread.java:102) Caused by: java.lang.ClassNotFoundException: org.eclipse.jdt.internal.compiler.batch.GCCMain not found in gnu.gcj.runtime.SystemClassLoader{urls=[], parent=gnu.gcj.runtime.ExtensionClassLoader{urls=[], parent=null}} at java.net.URLClassLoader.findClass(URLClassLoader.java:529) at gnu.gcj.runtime.SystemClassLoader.findClass(libgcj.so.9) at java.lang.ClassLoader.loadClass(libgcj.so.9) at java.lang.ClassLoader.loadClass(libgcj.so.9) at gnu.java.lang.MainThread.run(libgcj.so.9)