JAVA_HOME typically should only include the folder that contains the bin folder.

So in your case

export JAVA_HOME=/home/user/jdk1.7.0_02/

export PATH=$PATH:$JAVA_HOME/bin

In addition for finding the location of your java_home you can follow this command

which java

(This will return the path of the current java binary. Over here its /usr/bin/java)

ls -alh /usr/bin/java

( This will return true path to the symbolic link. Over here its /etc/alternatives/java.

ls -alh /etc/alternatives/java

( This will return true path to this symbolic link which is actual JAVA HOME path)

unset it

unset DYLD_LIBRARY_PATH

The bash reference manual says

Once a variable is set, it may be unset only by using the unset builtin command.

You can use /usr/libexec/java_home -v <version you want> to get the path you need for JAVA_HOME. For instance, to get the path to the 1.7 JDK you can run /usr/libexec/java_home -v 1.7 and it will return the path to the JDK. In your .profile or .bash_profile just add

export JAVA_HOME=`/usr/libexec/java_home -v <version>`

and you should be good. Alternatively, try and convince the maintainers of java tools you use to make use of this method to get the version they need.

To open '.bash_profile' type the following in terminal :

nano ~/.bash_profile 

and add the following line to the file:

export JAVA_HOME=`/usr/libexec/java_home -v <version>`

Press CTRL+X to exit the bash. Press 'Y' to save changes.

To check whether the path has been added, type following in terminal:

source ~/.bash_profile
echo $JAVA_HOME

I think JAVA_HOME is the best you can do. The command-line tools like java and javac will respect that environment variable, you can use /usr/libexec/java_home -v '1.7*' to give you a suitable value to put into JAVA_HOME in order to make command line tools use Java 7.

Copyexport JAVA_HOME="`/usr/libexec/java_home -v '1.7*'`"

But standard double-clickable application bundles don't use JDKs installed under /Library/Java at all. Old-style .app bundles using Apple's JavaApplicationStub will use Apple Java 6 from /System/Library/Frameworks, and new-style ones built with AppBundler without a bundled JRE will use the "public" JRE in /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home - that's hard-coded in the stub code and can't be changed, and you can't have two different public JREs installed at the same time.

Edit: I've had a look at VisualVM specifically, assuming you're using the "application bundle" version from the download page, and this particular app is not an AppBundler application, instead its main executable is a shell script that calls a number of other shell scripts and reads various configuration files. It defaults to picking the newest JDK from /Library/Java as long as that is 7u10 or later, or uses Java 6 if your Java 7 installation is update 9 or earlier. But unravelling the logic in the shell scripts it looks to me like you can specify a particular JDK using a configuration file.

Create a text file ~/Library/Application Support/VisualVM/1.3.6/etc/visualvm.conf (replace 1.3.6 with whatever version of VisualVM you're using) containing the line

Copyvisualvm_jdkhome="`/usr/libexec/java_home -v '1.7*'`"

and this will force it to choose Java 7 instead of 8.

Simply spoken, there is a whole hierarchy of configuration files that might have been updated in the past and that contain that setup.

There could bee a local .profile, .bashrc; or system-wide pendants for you. So, depending on the shell you are using, the version of Linux, ... there are various places to look at. See here for some guidance with bash.

You can start with a simple

grep JAVA_HOME .*

in your home directory. Next level of "escalation":

/etc/environment, /etc/profile, /etc/profile.d/, /etc/bashrc

$JAVA_HOME will already have a definition on many systems without explicitly declaring it in /etc/environment:

$ echo $JAVA_HOME
/usr/lib/jvm/java-8-oracle

That said, the unset command will eliminate a variable. From: Unix / Linux - Using Shell Variables

Unsetting Variables

Unsetting or deleting a variable directs the shell to remove the variable from the list of variables that it tracks. Once you unset a variable, you cannot access the stored value in the variable.

Following is the syntax to unset a defined variable using the unset command −

unset variable_name

The above command unsets the value of a defined variable. Here is a simple example that demonstrates how the command works −

#!/bin/sh

NAME="Zara Ali"
unset NAME
echo $NAME

In our case we can use:

$ echo $JAVA_HOME
/usr/lib/jvm/java-8-oracle
───────────────────────────────────────────────────────────────────────────────────────────
$ unset JAVA_HOME
───────────────────────────────────────────────────────────────────────────────────────────
$ echo $JAVA_HOME

───────────────────────────────────────────────────────────────────────────────────────────
$