How to find path where jdk installed?

  • I've installed jdk1.7.0.rpm package in RHEL6.
    Where I do find the path to execute my first java program?

    Possible duplicate of 18472

    Hi, Mohammad. It's not a stupid question, but one that has been answered in several places already - like this or this question.

    Just an PS: on MacOS, Java is usually installed at '/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home', where the version number could be different.

  • Try either of the two:

    $ which java

    $ whereis java

    For your first java program read this tutorial:

    "Hello World!" for Solaris OS and Linux

    Note these commands give different results. If you are interested in the non-symlink path use whereis java.

    I don't really think this answers the question. The `java` binary gets installed with the JRE, but if you're doing development you need JDK, which isn't necessarily installed in `which java` (which in my case is /usr/bin).

    `type java` is a more cross-platform method, as it's built into every major posix shell.

  • You can list the installed files with

    rpm -ql packagename
    

    You will see somewhere a bin directory with java executable

    But if the JDK RPM was correctly installed you should already find java in you path.

    Try

    javac MyFirstJavaClass.java
    

    and if everything compiles

    java MyFirstClass
    

    (If you didn't change anything the current directory . should already be in your class path)

    This should be the accepted answer IMO.

  • On RHEL7, I used

    locate openjdk
    

    and it led me to the /usr/lib/jvm/ directory which contained the directories:

    java-1.8.0-openjdk-1.8.0.161-0.b14.el7_4.x86_64/
    jre/
    jre-1.8.0/
    jre-1.8.0-openjdk/
    jre-1.8.0-openjdk-1.8.0.161-0.b14.el7_4.x86_64/
    jre-openjdk/
    

    Each of these contain a bin/java

    To find the full path of the symbolic link use:

    readlink -f $(which java)
    

    *Credit: Answer on Stack Overflow

    **Note: I'm answering here as it was the first result in Google

    This gave me mostly JDK6 even though `java -version` gave me 1.8. There was one link to the JDK8 folder near the top.

  • Since this question is RPM specific, rpm is the way to get started (as answered by @Matteo).

    rpm flags

    -q is short for --query
    -l is short for --list
    

    Example

    rpm -ql jdk1.8.0_20 | grep "jdk1.8.0_20/bin$"
    
    /usr/java/jdk1.8.0_20/bin
    

    Knowing this may be desirable for setting a user or application's $JAVA_HOME variable. This is often needed when a system has multiple versions of java installed, or multiple distributions of java installed, such as OpenJDK and Oracle/Sun.

    $JAVA_HOME Example

    In the ~/.bash_profile, or related file (.bashrc, .zshrc, .cshrc, setenv.sh), something similar to the below may be used.

    JAVA_HOME='/usr/java/jdk1.8.0_20'
    export JAVA_HOME
    PATH="$JAVA_HOME/bin:$PATH"
    export PATH
    

    If you would like more control over where Java gets installed, such as in /opt, then the tarball can be used instead of the RPM file.


    Other similar questions, are asking about how to find any binary or file, in the general case.

    In general, I highly recommend using the mlocate package for finding things on a Red Hat based Linux's file system.

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Content dated before 6/26/2020 9:53 AM