第一次在linux下用java编程出错，求助

moonriver2001

操作系统为redhat9.0

[root@localhost root]# javac Addition.java
[root@localhost root]# java Addition
Exception in thread "main" java.lang.VerifyError: verification failed at PC 123
in javax.swing.JComponent:getListeners((Ljava.lang.Class;)[Ljava.util.EventListener;): incompatible return type
at 0x40268e17: java.lang.Throwable.Throwable(java.lang.String) (/usr/lib/./libgcj.so.3)
at 0x4025bc8e: java.lang.Error.Error(java.lang.String) (/usr/lib/./libgcj.so.3)
at 0x4025d6b6: java.lang.LinkageError.LinkageError(java.lang.String) (/usr/lib/./libgcj.so.3)
at 0x402691b6: java.lang.VerifyError.VerifyError(java.lang.String) (/usr/lib/./libgcj.so.3)
at 0x4023f5a9: _Jv_BytecodeVerifier.verify_fail(byte, int) (/usr/lib/./libgcj.so.3)
at 0x40232c51: _Jv_BytecodeVerifier.verify_instructions_0() (/usr/lib/./libgcj.so.3)
at 0x40231857: _Jv_VerifyMethod(_Jv_InterpMethod) (/usr/lib/./libgcj.so.3)
at 0x40229ae4: _Jv_PrepareClass(java.lang.Class) (/usr/lib/./libgcj.so.3)
at 0x40248028: java.lang.ClassLoader.linkClass0(java.lang.Class) (/usr/lib/./libgcj.so.3)
at 0x4025acb3: java.lang.ClassLoader.resolveClass0(java.lang.Class) (/usr/lib/./libgcj.so.3)
at 0x402299cb: _Jv_PrepareClass(java.lang.Class) (/usr/lib/./libgcj.so.3)
at 0x40248028: java.lang.ClassLoader.linkClass0(java.lang.Class) (/usr/lib/./libgcj.so.3)
at 0x4025acb3: java.lang.ClassLoader.resolveClass0(java.lang.Class) (/usr/lib/./libgcj.so.3)
at 0x4024646c: java.lang.Class.initializeClass() (/usr/lib/./libgcj.so.3)
at 0x402296af: _Jv_ResolvePoolEntry(java.lang.Class, int) (/usr/lib/./libgcj.so.3)
at 0x40230827: _Jv_InterpMethod.continue1(_Jv_InterpMethodInvocation) (/usr/lib/./libgcj.so.3)
at 0x40230ff4: _Jv_InterpMethod.run(ffi_cif, void, ffi_raw, _Jv_InterpMethodInvocation) (/usr/lib/./libgcj.so.3)
at 0x4022e504: _Jv_InterpMethod.run_normal(ffi_cif, void, ffi_raw, void) (/usr/lib/./libgcj.so.3)
at 0x4038305c: ?? (??:0)
at 0x40242dd8: gnu.gcj.runtime.FirstThread.call_main() (/usr/lib/./libgcj.so.3)
at 0x402ad02d: gnu.gcj.runtime.FirstThread.run() (/usr/lib/./libgcj.so.3)
at 0x4024fc4c: _Jv_ThreadRun(java.lang.Thread) (/usr/lib/./libgcj.so.3)
at 0x4021c8ac: _Jv_RunMain(java.lang.Class, byte const, int, byte const, boolean) (/usr/lib/./libgcj.so.3)
at 0x08048910: ?? (??:0)
at 0x420156a4: __libc_start_main (/lib/tls/libc.so.6)
at 0x080486c1: ?? (??:0)
[root@localhost root]#


我的/etc/profile为
# /etc/profile

# System wide environment and startup programs, for login setup
# Functions and aliases go in /etc/bashrc

pathmunge () {
if ! echo $PATH | /bin/egrep -q "(^|$1($|" ; then
if [ "$2" = "after" ] ; then
PATH=$PATH:$1
else
PATH=$1:$PATH
fi
fi
}

# Path manipulation
if [ `id -u` = 0 ]; then
pathmunge /sbin
pathmunge /usr/sbin
pathmunge /usr/local/sbin
fi

pathmunge /usr/X11R6/bin after

unset pathmunge

# No core files by default
ulimit -S -c 0 > /dev/null 2>&1

USER="`id -un`"
LOGNAME=$USER
MAIL="/var/spool/mail/$USER"

HOSTNAME=`/bin/hostname`
HISTSIZE=1000

if [ -z "$INPUTRC" -a ! -f "$HOME/.inputrc" ]; then
INPUTRC=/etc/inputrc
fi

export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE INPUTRC

for i in /etc/profile.d/*.sh ; do
if [ -r "$i" ]; then
. $i
fi
done

unset i
#java
#如果你安装的j2sdk的路径不一样,请自行修改
JAVA_HOME=/usr/java/j2sdk1.4.2
export JAVA_HOME
CLASSPATH=.:/usr/java/j2sdk1.4.2/lib/tools.jar:/usr/java/j2sdk1.4.2/jre/lib/rt.jar:/root/javas
export CLASSPATH
PATH=$PATH:$JAVA_HOME/bin:$JAVA_HOME/jre/bin
export PATH
JRE=/usr/java/j2sdk1.4.2/jre
export JRE

原代码为
import javax.swing.JOptionPane;



public class Addition {

public static void main(String args[]){

String firstNumber, secondNumber;

int number1, number2, sum;



firstNumber = JOptionPane.showInputDialog("Enter first integer");

secondNumber = JOptionPane.showInputDialog("Enter second integer");



number1 = Integer.parseInt(firstNumber);

number2 = Integer.parseInt(secondNumber);



sum = number1 + number2;



JOptionPane.showMessageDialog(null, "The sum is " + sum, "Results", JOptionPane.PLAIN_MESSAGE);



System.exit(0);

}

}