Java command not found on Linux

问题

In Oracle Enterprise Linux when I type java I am getting

bash: java: command not found

I have installed Java 1.6 and I have the following

sudo update-alternatives --config java

There are 2 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
*  1           /usr/lib/jvm/jre-1.4.2-gcj/bin/java
 + 2           /usr/java/jre1.6.0_24/bin/java

How can I resolve this issue?

Thanks

回答1:

You can add one of the Java path to PATH variable using the following command.

export PATH=$PATH:/usr/java/jre1.6.0_24/bin/

You can add this line to .bashrc file in your home directory. Adding this to .bashrc will ensure everytime you open bash it will be PATH variable is updated.

回答2:

I had these choices:

-----------------------------------------------
*  1           /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/java
 + 2           /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java
   3           /home/ec2-user/local/java/jre1.7.0_25/bin/java

When I chose 3, it didn't work. When I chose 2, it did work.

回答3:

I found the best way for me was to download unzip then symlink your new usr/java/jre-version/bin/java to your main bin as java.

回答4:

I use the following script to update the default alternative after install jdk.

#!/bin/bash
export JAVA_BIN_DIR=/usr/java/default/bin # replace with your installed directory
cd ${JAVA_BIN_DIR}
a=(java javac javadoc javah javap javaws)
for exe in ${a[@]}; do
    sudo update-alternatives --install "/usr/bin/${exe}" "${exe}" "${JAVA_BIN_DIR}/${exe}" 1
    sudo update-alternatives --set ${exe} ${JAVA_BIN_DIR}/${exe}
done

回答5:

1. Execute: vi ~/.bashrc OR vi ~/.bash_profile

(if above command will not allow to update the .bashrc file then you can open this file in notepad by writing command at terminal i.e. "leafpad ~/.bashrc")

2. add line : export JAVA_HOME=/usr/java/jre1.6.0_24
3. save the file (by using shift + Z + Z)
4. source ~/.bashrc OR source ~/.bash_profile
5. Execute : echo $JAVA_HOME (Output should print the path)

来源：https://stackoverflow.com/questions/11237872/java-command-not-found-on-linux