FULL PRODUCT VERSION :
The executable from jdk-6-linux-i586.bin doesn't startup at all:
stefan@ds9 ~ $ java
Error occurred during initialization of VM
java.nio.BufferOverflowException
        at java.nio.charset.CoderResult.throwException(CoderResult.java:259)
        at java.lang.StringCoding$StringDecoder.decode(StringCoding.java:142)
        at java.lang.StringCoding.decode(StringCoding.java:173)
        at java.lang.String.<init>(String.java:444)
        at java.lang.String.<init>(String.java:516)
        at java.lang.System.initProperties(Native Method)
        at java.lang.System.initializeSystemClass(System.java:1072)
stefan@ds9 ~ $ java

  From the nightly build:
stefan@ds9 ~ $ java -version
java version "1.6.0_01-ea"
Java(TM) SE Runtime Environment (build 1.6.0_01-ea-b01)
Java HotSpot(TM) Client VM (build 1.6.0_01-ea-b01, mixed mode, sharing)


ADDITIONAL OS VERSION INFORMATION :
Linux ds9 2.6.18-gentoo-r3 #1 SMP PREEMPT Fri Dec 1 00:02:27 CET 2006 i686 AMD Athlon(tm) XP 2100+ AuthenticAMD GNU/Linux

A DESCRIPTION OF THE PROBLEM :
  From jdk-6-linux-i586.bin: see above.
  From 1.6.0_01-ea (looks similar for other java applications):
Exception in thread "main" java.lang.ExceptionInInitializerError
        at java.lang.System.getenv(System.java:832)
        at java.awt.GraphicsEnvironment$1.run(GraphicsEnvironment.java:136)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.awt.GraphicsEnvironment.getHeadlessProperty(GraphicsEnvironment.java:125)
        at java.awt.GraphicsEnvironment.isHeadless(GraphicsEnvironment.java:102)
        at java.lang.ClassLoader$NativeLibrary.load(Native Method)
        at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1751)
        at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1668)
        at java.lang.Runtime.loadLibrary0(Runtime.java:823)
        at java.lang.System.loadLibrary(System.java:1030)
        at sun.security.action.LoadLibraryAction.run(LoadLibraryAction.java:50)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.awt.Toolkit.loadLibraries(Toolkit.java:1594)
        at java.awt.Toolkit.<clinit>(Toolkit.java:1616)
        at java.awt.Color.<clinit>(Color.java:263)
        at javax.swing.plaf.metal.MetalTheme.<clinit>(MetalTheme.java:59)
        at javax.swing.plaf.metal.MetalLookAndFeel.getCurrentTheme(MetalLookAndFeel.java:1673)
        at javax.swing.plaf.metal.MetalLookAndFeel.createDefaultTheme(MetalLookAndFeel.java:1568)
        at javax.swing.plaf.metal.MetalLookAndFeel.getDefaults(MetalLookAndFeel.java:1590)
        at javax.swing.UIManager.setLookAndFeel(UIManager.java:537)
        at javax.swing.UIManager.setLookAndFeel(UIManager.java:577)
        at xasche.Xasche.main(Xasche.java:44)
Caused by: java.nio.BufferOverflowException
        at java.nio.charset.CoderResult.throwException(CoderResult.java:259)
        at java.lang.StringCoding$StringDecoder.decode(StringCoding.java:142)
        at java.lang.StringCoding.decode(StringCoding.java:173)
        at java.lang.StringCoding.decode(StringCoding.java:185)
        at java.lang.String.<init>(String.java:571)
        at java.lang.String.<init>(String.java:594)
        at java.lang.ProcessEnvironment$Value.valueOf(ProcessEnvironment.java:190)
        at java.lang.ProcessEnvironment.<clinit>(ProcessEnvironment.java:58)
        ... 22 more


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
lrwxrwxrwx 1 root root 5 11. Jan 23:16 java -> java6
lrwxrwxrwx 1 root root 11 12. Jan 00:10 java6 -> jdk1.6.0_01
stefan@ds9 ~ $ echo $JAVAC
/usr/local/java/bin/javac
stefan@ds9 ~ $ echo $JAVA_HOME
/usr/local/java
stefan@ds9 ~ $ echo $JDK_HOME
/usr/local/java


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
A running application
ACTUAL -
Caused by: java.nio.BufferOverflowException
        at java.nio.charset.CoderResult.throwException(CoderResult.java:259)
        at java.lang.StringCoding$StringDecoder.decode(StringCoding.java:142)
        at java.lang.StringCoding.decode(StringCoding.java:173)
        at java.lang.StringCoding.decode(StringCoding.java:185)
        at java.lang.String.<init>(String.java:571)
        at java.lang.String.<init>(String.java:594)

ERROR MESSAGES/STACK TRACES THAT OCCUR :
The results of an eclipse run:
!SESSION Fri Jan 12 00:16:59 CET 2007 ------------------------------------------
!ENTRY org.eclipse.core.launcher 4 0 2007-01-12 00:16:59.523
!MESSAGE Exception launching the Eclipse Platform:
!STACK
java.nio.BufferOverflowException
        at java.nio.charset.CoderResult.throwException(CoderResult.java:259)
        at java.lang.StringCoding$StringDecoder.decode(StringCoding.java:142)
        at java.lang.StringCoding.decode(StringCoding.java:173)
        at java.lang.String.<init>(String.java:444)
        at java.util.jar.Attributes.read(Attributes.java:384)
        at java.util.jar.Manifest.read(Manifest.java:182)
        at java.util.jar.Manifest.<init>(Manifest.java:52)
        at java.util.jar.JarFile.getManifestFromReference(JarFile.java:160)
        at java.util.jar.JarFile.getManifest(JarFile.java:146)
        at sun.misc.URLClassPath$JarLoader$2.getManifest(URLClassPath.java:693)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:221)
        at java.net.URLClassLoader.access$000(URLClassLoader.java:56)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
        at org.eclipse.core.launcher.Main.invokeFramework(Main.java:333)
        at org.eclipse.core.launcher.Main.basicRun(Main.java:280)
        at org.eclipse.core.launcher.Main.run(Main.java:977)
        at org.eclipse.core.launcher.Main.main(Main.java:952)


REPRODUCIBILITY :
This bug can be reproduced always.