I have downloaded `apache-tomcat-7.0.35`. My JDK version is `jdk1.6.0_27`. 

How do I configure `CATALINA_HOME` as an environment variable and how do I run Tomcat server under Windows 7?

How to set CATALINA_HOME variable in windows 7?

How can I setup `JAVA_HOME` path without having to set it each time I restart my machine?

I&#39;ve used the following ways when trying to set JAVA_HOME on my Ubuntu machine:

1) From terminal I&#39;ve executed the following command:

    export JAVA_HOME=/usr/lib/jvm/jdk1.7.0

2) I&#39;ve edited the `/etc/enviroment` file directly to add `JAVA_HOME` path in it

What&#39;s really strange is that if I test `JAVA_HOME` using the `echo` command after an of the above two ways, I can see it is set correctly, but if I restart, logout/ login again or even after working on the machine for a while the `JAVA_HOME` is no more set and I have to set it again using any of the above two ways.

So can someone please tell me what I am doing wrong here?

How to set JAVA_HOME path on Ubuntu?

I am new to Linux system and there seem to be too many Java folders. 

java -version gives me:

- java version &quot;1.7.0_55&quot;
- OpenJDK Runtime Environment (rhel-2.4.7.1.el6_5-x86_64 u55-b13)
- OpenJDK 64-Bit Server VM (build 24.51-b03, mixed mode)

When I am trying to build a Maven project , I am getting error:

        
    Error: JAVA_HOME is not defined correctly.
    We cannot execute /usr/java/jdk1.7.0_05/bin/java

Could you please tell me which files I need to modify for root as well as not-root user and where exactly is java located?

How to set JAVA_HOME in Linux for all users

I know it&#39;s installed because when I type:

    $java -version

I get:

    OpenJDK Runtime Environment (IcedTea6 1.12.5) (6b27-1.12.5-0ubuntu0.12.04.1)
    OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode)

And when I type:

    $locate jdk

I get:

    /home/arturo/Documents/2012a/sys/java/jre/glnxa64/jre/lib/servicetag/jdk_header.png
    /usr/share/app-install/desktop/openjdk-6-jre:openjdk-6-java.desktop
    /usr/share/app-install/desktop/openjdk-7-jre:openjdk-7-java.desktop
    /usr/share/app-install/icons/openjdk-6.png
    /usr/share/app-install/icons/openjdk-7.png

What worries me about the first item in the list is that the 2012a folder is my MATLAB folder and not a standard &#39;usr/lib&#39; folder. I&#39;m really confused on where the JDK and JRE got installed, because I need to set the $JAVA_HOME path pointing to the folder. Where am I missing something?

Where is the Java SDK folder in my computer? Ubuntu 12.04

In Ubuntu, I&#39;d like to switch my JAVA_HOME environment variable back and forth between Java 5 and 6.

I open a terminal and type in the following to set the JAVA_HOME environment variable:

    export JAVA_HOME=/usr/lib/jvm/java-1.5.0-sun

And in that same terminal window, I type the following to check that the environment variable has been updated:

    echo $JAVA_HOME

And I see **/usr/lib/jvm/java-1.5.0-sun** which is what I&#39;m expecting to see.  In addition, I modify ~/.profile and set the JAVA_HOME environment variable to /usr/lib/jvm/java-1.5.0-sun.

And now for the problem--when I open a new terminal window and I check my JAVA_HOME environment variable by typing in **echo $JAVA_HOME** I see that my JAVA_HOME environment variable has been reverted back to Java 6.  When I reboot my machine (or log out and back in, I suppose) the JAVA_HOME environment variable is set to Java 5 (presumably because of the modification I made in my ~/.profile).

Is there a way around this so that I can change my JAVA_HOME environment without having to log out and back in (AND make that environment variable change *stick* in all new terminal windows)?

Make $JAVA_HOME easily changable in Ubuntu

How do I change the value of `JAVA_HOME` in Ubuntu to point to Oracle&#39;s Java? 

Should it point to `java-6-sun` or `java-6-sun-1.6.0.24` ?

How to set Oracle&#39;s Java as the default Java in Ubuntu?

(Wasn&#39;t sure if this should go on SU... migration is certainly an option, but more programmers read questions here, so here goes).

I am running Mac OS X 10.8.4, and I have Apple&#39;s JDK 1.6.0_51 installed as well as Oracle&#39;s JDK 1.7.0_25. I recently installed Oracle&#39;s 1.8 preview JDK for some pre-release software that requires it. Now, when I run /usr/libexec/java_home, I get this:

    $ /usr/libexec/java_home -V
    Matching Java Virtual Machines (4):
        1.8.0, x86_64:	&quot;Java SE 8&quot;	/Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home
        1.7.0_25, x86_64:	&quot;Java SE 7&quot;	/Library/Java/JavaVirtualMachines/jdk1.7.0_25.jdk/Contents/Home
        1.6.0_51-b11-457, x86_64:	&quot;Java SE 6&quot;	/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
        1.6.0_51-b11-457, i386:	&quot;Java SE 6&quot;	/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home

Great.

However, running:

    $ java -version

Returns:

    java version &quot;1.8.0-ea&quot;

That means that the default version of Java is currently the pre-release version, which breaks some &quot;normal&quot; packages (in my case, VisualVM).

I can&#39;t set `JAVA_HOME` because launching applications ignores environment variables, even when launching from the command line (e.g. `$ open /Applications/VisualVM.app`).

So, is there a file I can edit where I can set my JVM ordering preferences *globally*?

(Please don&#39;t tell me to launch the Java Preferences Panel because that simply does not work: it does not contain anything useful and only lists one of the 4 JVMs that I have installed.)

**Update**:

Oracle JVMs live in `/Library/Java/JavaVirtualMachines`. Re-naming the JDK 1.8 directory to `jdk1.8.0.jvm.xyz` does not change anything: `java_home` still finds it in the right place, and running /usr/bin/java still executes the 1.8 JVM. This is not an issue with synlinks, etc.

**Answers to Similar Questions**

While [this answer][1] offers what amounts to a hack that will remove versions of Java from being picked up by java_home, it still does not answer this question of *how* java_home chooses its default and whether or not users can [non-destructively set it][2].


  [1]: https://stackoverflow.com/a/44169445/1090666
  [2]: https://stackoverflow.com/a/20994919/1090666

How can I change Mac OS&#39;s default Java VM returned from /usr/libexec/java_home

I pointed the `JAVA_HOME` to `C:\Program Files (x86)\Java\jre7`. It works fine. Afterwards, I unzipped ant and set up the environment variables related to Ant, I got the following error messages after typing `&quot;ant -version&quot;`

 ![image][1]

  [1]: http://i.stack.imgur.com/CZc7p.png

I searched this forum. Looks like one solution is to point Java to JDK instead of JRE. I am not exactly sure whether this should be the solution. In other words, in general, which one should JAVA_HOME point to? JDK or JRE?

Should JAVA_HOME point to JDK or JRE?

Many java based application requires to set JAVA_HOME env variable. What&#39;s the purpose of this variable?

what is the reason for the existence of the JAVA_HOME environment variable?

I am trying to set `JAVA_HOME` by entering `export JAVA_HOME=/Library/Java/Home` at terminal.
It sets the `JAVA_HOME` for current session. 

How can I set it permanently?

How to set JAVA_HOME in Mac permanently?

I am new in developing native app using Salesforce SDK. I tried to create android project from command line using forcedroid tool but there is problem in setting environment variable named ANDROID_HOME.

But i don&#39;t know how to set this variable.

I am attaching screenshot to describe my problem correctly.


![enter image description here][1]


  [1]: http://i.stack.imgur.com/a04Kh.png

Set ANDROID_HOME environment variable in mac

In Windows, `JAVA_HOME` must point to the JDK installation folder (so that `JAVA_HOME/bin` contains all executables and `JAVA_HOME/libs` contains all default `jar` libraries).

If I download Sun&#39;s JDK bundle and installs it in Linux, it is the same procedure.

However, I need to use Kubuntu&#39;s default OpenJDK package. The problem is that all executables are placed in `/usr/bin`. But the jars are placed in `/usr/share/java`. Since they are not under the same `JAVA_HOME` folder I&#39;m having trouble with Grails and maybe there will be trouble with other applications that expect the standard Java structure.

1. If I use:

        JAVA_HOME=/usr

 All applications and scripts that want to use any Java executable can use the standard procedure `call $JAVA_HOME/bin/executable`. However, since the jars are in a different place, they are not always found (example: in grails I&#39;m getting `ClassDefNotFound` for `native2ascii`).

2. On the other hand, if I use:

        JAVA_HOME=/usr/share/java

 None of the Java executables (`java`, `javac`, etc.) can be found.

So, what is the correct way of handling the `JAVA_HOME` variable in a Debian-based Linux?

Thanks for your help,
Luis

What is the correct target for the JAVA_HOME environment variable for a Linux OpenJDK Debian-based distribution?

I went to the Environment Variables in &#39;System&#39; in the control panel and made two new variables, one for user variables and one for system variables. Both were named JAVA_HOME and both pointing to

&gt;    C:\Sun\SDK\jdk\bin

But for some reason, I still get the below error when running a Java command...

    BUILD FAILED
    C:\Users\Derek\Desktop\eclipse\eclipse\glassfish\setup.xml:161: The following error  occurred while executing this line:
    C:\Users\Derek\Desktop\eclipse\eclipse\glassfish\setup.xml:141: The following error occurred while executing this line:
    C:\Users\Derek\Desktop\eclipse\eclipse\glassfish\setup.xml:137: Please set java.home to a JDK installation

    Total time: 1 second
    C:\Users\Derek\Desktop\eclipse\eclipse\glassfish&gt;lib\ant\bin\ant -f setup.xml
    Unable to locate tools.jar. Expected to find it in C:\Program Files\Java\jre6\lib\tools.jar
    Buildfile: setup.xml

How can I fix this problem?


How to set java_home on Windows 7?

I tried to open Android Device Monitor and the Studio showed me this message =-O :
[![need to install Java SE 6 runtime error][1]][1]

It surprised me, because how have I been able to develop Android apps if I didn&#39;t have any Java installed?! Actually, Android Studio comes with bundled JDK/JRE (located in `/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home`), but it is not found by the system: executed `usr/libexec/java_home` gives

    Unable to find any JVMs matching version &quot;(null)&quot;.
    No Java runtime present, try --request to install.

Setting `$JAVA_HOME` to `/Applications/Android Studio.app/Contents/jre/jdk/Contents/Home` did not help — `source .bash_profile` doesn&#39;t like that it&#39;s a directory.

QUESTION: I don&#39;t want to install new JDK if I already have one inside Android Studio. How do I set it as system default?

  [1]: https://i.stack.imgur.com/SUlHl.png

Using JDK that is bundled inside Android Studio as JAVA_HOME on Mac

I installed java and set the path environment and when I run `echo $JAVA_HOME` in the terminal I get the following output:

    /usr/lib/jvm/java-7-oracle/jre/bin/java

I Also installed `apache-maven` and changed `environment` file and now it looks like this:

    JAVA_HOME=&quot;/usr/lib/jvm/java-7-oracle/jre/bin/java&quot;
    M2_HOME=/usr/local/apache-maven/apache-maven-3.0.5
    M2=$M2_HOME/bin
    MAVEN_OPTS=&quot;-Xms256m -Xmx512m&quot;
    PATH=$M2:$PATH

But when I execute `mvn --version` I get a warning:

    Error: JAVA_HOME is not defined correctly.
      We cannot execute /usr/lib/jvm/java-7-oracle/jre/bin/java/bin/java

Can not find out why it repeats in the end `/bin/java/bin/java`

Error: JAVA_HOME is not defined correctly executing maven

I just downloaded the Android Studio. While trying to run it, I had to modify the environment variable and add

&gt; JAVA_HOME

 and 

&gt; C:\Progra~2\Java\jdk1.6.0_22

Once I finished that hurdle, now I am receiving another error:

    The environment variable JAVA_HOME (with the value of *C:\Progra~2\Java\jdk1.6.0_22*) does not point to a valid JVM installation.

I looked through other similar questions and I was asked to check the version, so I did the following in CMD:

    C:\Users\Andre&gt;java -version
    java version &quot;1.6.0_22&quot;
    Java(TM) SE Runtime Environment (build 1.6.0_22-b04)
    Java HotSpot(TM) Client VM (build 17.1-b03, mixed mode, sharing)

    C:\Users\Andre&gt;javac -version
    javac 1.6.0_22


From the results it seems like I have JVM.

I also tried these paths for JAVA_HOME, I closed and reopened a new CMD window each time

    C:\Program Files (x86)\Java\jre7
    C:\Program Files (x86)\Java\jre6
    C:\Program Files (x86)\Java\jdk1.6.0_22
    C:\Program Files (x86)\Java\jre7\bin
    C:\Program Files (x86)\Java\jre6\bin
    C:\Program Files (x86)\Java\jdk1.6.0_22\bin

Installing Android Studio, does not point to a valid JVM installation error

I get the error: 

C:\dev\ws\springapp\build.xml:81: 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 &quot;C:\Program Files\Java\jre6&quot;


But I have clearly set my JAVA_HOME to be C:\Program Files\Java\jdk1.6.0_14

Where is ANT getting this value?

Why does ANT tell me that JAVA_HOME is wrong when it is not?

I have Java 1.6 and Tomcat 5.5 installed on my system.

But Tomcat 5.5 accesses Java 1.5 and hence as the outcome I get the error `Bad version number in .class file` while executing java code with JSP.

How can I change the Tomcat version to Java 1.6?

**UPDATE**

I tried changing the JVM that the tomcat5w.exe is pointing to the version 1.6 and now I am out of the `Bad version in .class file` error. But now, I get the following error.

    exception

    org.apache.jasper.JasperException
	org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:498)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:411)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:308)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:259)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:729)

    root cause

    java.lang.NullPointerException
	myfirst.SearchLink.checkURL(SearchLink.java:20)
	org.apache.jsp.Test_jsp._jspService(Test_jsp.java:52)
	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:369)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:308)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:259)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:729)

What might be the root cause?

All Java Home Solutions on Gang of Coders

Total of 18 Java Home Solutions