General :: Variable Expansion In .bashrc Not Working?

In my .bashrc file, I am attempting to set JAVA_PATH to a local path, using the HOME environment variable or '~' symbol as shown in the following examples.Using ${HOME}

export JAVA_PATH='${HOME}/Software/java/jdk1.6.0_24'

When I attempt to use ${JAVA_HOME} in a my ${PATH} javec is not found. To debug it, I tried a simple ls command:

ls ${JAVA_HOME}

and get the following error:

ls: ${HOME}/Software/java/jdk1.6.0_24/: No such file or directory

Using '~': Trying to use '~' symbol as follows:

export JAVA_PATH='~/Software/java/jdk1.6.0_24'

the ls command results in the same error, however javac is found.I prefer the '~' symbol anyway, but would like to understand why the ls command does not work for either, and why it seems as though ${HOME} is not being expanded.