Weird about libstdc++.so.5 Error

Yesterday , I try to setup Hadoop on eclipse on Ubuntu in Virtual Box.

I found Error about Missing some class. It say
"BUILD FAILED
build.xml :316: Unable to find a javac compiler
com.sun.tools.javac.Main is not on the classpath.
Perhaps JAVA_HOME does not point to the JDK.
It is currently set to "/usr/lib/jvm/java-6-openjdk/jre"
".

First , you should download JDK from sun micro system and install it's packages.
Don't forget to "chmod +x " if you can't run install command.
or you may can "sudo apt-get install " that something I don't know too.

if you encounter problem about
"./java_ee_sdk_linux.bin: error while loading shared libraries: libstdc++.so.5: cannot open shared object file: No such file or directory"
or similar to this you may get the wrong .bin file.
Try to download Other file that not the same as old one.

If you got the right .bin file now. Don't forget to "chmod +x " if you can't run install command.
then run "./".
Additionally , you may move the JDK folder to the well-manner category "/usr/lib/jvm".
(If you can't use copy command then omit it. use move instead it then finish successful.)

After you finish install jdk then do the last step to let's Ant correctly run.

Lastly , Add tools.jar to Ant Runtime Classpath.The Problem solved.