Develop Reference

Running Netbeans for Java

I have a problem with running Netbeans for Java development..
When I try to run it I get
I checked the config located in <netbeans_dir>/etc/netbeans.conf and found following setting:
netbeans_jdkhome="/usr/"
So, I checked java and javac:
>>java -version
openjdk version "1.8.0_151"
OpenJDK Runtime Environment (build 1.8.0_151-8u151-b12-0ubuntu0.16.04.2-b12)
OpenJDK 64-Bit Server VM (build 25.151-b12, mixed mode)
>>whereis java
java: /usr/bin/java /usr/share/java /usr/share/man/man1/java.1.gz
>>javac -version
javac 1.8.0_151
>>whereis javac
javac: /usr/bin/javac /usr/share/man/man1/javac.1.gz
So I updated netbeans_jdkhome to /usr/bin/javac. Now, when I try to run Netbeans I get
Cannot find java. Please use the --jdkhome switch.
I also tried to reinstall Java according to this instruction but once I did and changed jdkhome to /usr/lib/jvm/java-8-openjdk I still get Cannot find java.
What should I enter to run Netbeans properly?

Tools -> Java Platforms -> Add platform should display something like this:
Notice that Platform folder has small rectangle that indicates it can be chosen.

Error: could not find libjava.so, Error: could not find Java 2 Runtime Environment

I uninstalled java j2sdk1.4.2_12 java on my Linux Server and Install jdk1.6.0_21,
but when I am trying to run any script I am getting following Error
Error: could not find libjava.so
Error: could not find Java 2 Runtime Environment.
I already set classPath and Path like :
In vi ~/.bashrc
export JAVA_HOME=/home/java/jdk1.6.0_21/
export PATH=$PATH:/home/java/jdk1.6.0_21/bin
export set CLASSPATH=/usr/java/j2sdk1.4.2_12/lib/mysql-connector-java-5.1.6-bin.jar: /home/java/jdk1.6.0_21/jre/lib:/root/mis/mod:$CLASSPATH
ulimit -c unlimited
IN vi ~/.bash_profile
JAVA_HOME=/home/java/jdk1.6.0_21/
PATH=$PATH:$HOME/bin:$HOME/mis/mod:
PATH=/home/java/jdk1.6.0_21/bin:$PATH
CLASSPATH=$CLASSPATH:/home/java/jdk1.6.0_21/lib:.:
export JAVA_HOME
export PATH
export CLASSPATH
unset USERNAME
When I run following Commands
which java
/home/java/jdk1.6.0_21/bin/java
java -version
java version "1.6.0_21"
Java(TM) SE Runtime Environment (build 1.6.0_21-b06)
Java HotSpot(TM) Server VM (build 17.0-b16, mixed mode)
I am not getting where is the issue.
Can Any one help me ?

I encounter this issue before. It turns out there are 2 javac program sitting on my machine.
They are in /usr/bin/javac and /bin/javac. My system used the /bin/javac one. The right path for me is /usr/bin/javac. Removing /bin/javac helped

I faced the same issue, and it disppeared by just shutting down the CentOS VM and then starting again. Then type in javac command again to check.

while running mvn it throws error of java home not defined

I have mvn and java installed in my machine.
Still it throws JAVA_HOME is not defined correctly.:
mvn clean compile install -DskipTests
Error: JAVA_HOME is not defined correctly.
We cannot execute /opt/software/jdk1.7.0_65/bin/java
ijaz#ijaz20:~/codebase/central-repo/core-container$ java -version
java version "1.7.0_60"
Java(TM) SE Runtime Environment (build 1.7.0_60-b19)
Java HotSpot(TM) 64-Bit Server VM (build 24.60-b09, mixed mode)
ijaz#ijaz20:~/codebase/central-repo/core-container$

You have a problem with your java version:
The JAVA_HOME is set to /opt/software/jdk1.7.0_65/
And if you rung java --version you get the version 1.7.0_60
1.7.0_65 is not equals 1.7.0_60
So you have to change your JAVA_HOME variable.

JAVA_HOME is currently set, or defaulting, to /opt/software/jdk1.7.0_65/bin/java, which is not correct, tha's the location of the java binary, not the installation.
Try setting JAVA_HOME to the actual java home:
export JAVA_HOME="/opt/software/jdk1.7.0_65/"

Try the following:
$ which java
If that doesn't give you
/opt/software/jdk1.7.0_65/bin/java
then your JAVA_HOME is set improperly. Specifically, it appears that you currently have JDK 7 Update 60 installed, but JAVA_HOME is pointing to a non-existent JDK 7 Update 65. Fix your JAVA_HOME accordingly.
which java could also give you a location which has a symbolic link to the real location of the executable; you can check that with
$ ls -l `which java`
to see where it's pointing to.

error in setting java home environment variables ubuntu

i am new to ubuntu .initially i installed java in Ubuntu.
But i haven't set any envionment variables
After that installed maven build tool to build java package.when i compiled with build tool it shows some error says generic supports after 1.3 packages.
so i realize it JDK runs with 1.3. so i need set java environment variables for latest version
so in my Terminal java -version shows
beeshma#ubuntu:~$ java -version
java version "1.7.0_45"
Java(TM) SE Runtime Environment (build 1.7.0_45-b18)
Java HotSpot(TM) 64-Bit Server VM (build 24.45-b08, mixed mode)
and i set java environment variables in through below steps
[https://askubuntu.com/questions/277806/how-to-set-java-home][1]
sudo gedit ~/.bashrc
Now go to end of file and add the following lines:
export JAVA_HOME=/path/to/jdk/folder
#usually /usr/java/jdk or /usr/lib/java/jdk
export PATH=$PATH:$JAVA_HOME/bin
Now in terminal type:
sudo source ~/.bashrc
This will make it appear on every terminal if open.
Now you can cross check it by typing following line in terminal
$echo $PATH
/usr/java/jdk1.7.0_45//bin:/home/beeshma/bin:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/usr/java/jdk1.7.0_45//bin
What my question when i execute mvn --help
Fallowing error is coming
beeshma#ubuntu:~$ mvn -version
Error: JAVA_HOME is not defined correctly.
**We cannot execute /usr/java/jdk1.7.0_45//bin/java**

Try changing your export to:
export JAVA_HOME=$(/usr/java/jdk1.7.0_45)

Two things:
Try if /usr/java/jdk1.7.0_45//bin/java is indeed present.
See if the beeshma user has the permissions to 'execute' java.
Bonus: remove the trailing / in your JAVA_HOME value.

You can install the JDK with the following command:
$sudo apt install default-jdk
The above command also sets the java environment variable automatically

Java runtime not found in OSX 10.9.1 while running solR

I want to run solR in mac OSX 10.9.1. So I installed JRE latest version. Then, I downloaded solR and expanded the folder. But when I try to run this jar file in example folder, I get this msg "no java runtime present", mentioned below.
Do I need to add JAVA_HOME env variable like we do in windows? If so, please tell me how.
Ananyas-MacBook-Pro:~ ananya$ /Library/Internet\ Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java -version
java version "1.7.0_51"
Java(TM) SE Runtime Environment (build
1.7.0_51-b13)
Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)
Ananyas-MacBook-Pro:~ ananya$ cd /Users/ananya/Desktop/VT\ study/solr-4.6.1/example
Ananyas-MacBook-Pro:example ananya$ java -jar start.jar
No Java runtime present, requesting install.
Ananyas-MacBook-Pro:example ananya$
Thanks.

"Do I need to add JAVA_HOME env variable like we do in windows?"
Test to see if/where Java is on your path in a terminal:
echo $JAVA_HOME
If the path to Java is wrong or missing you can add and Environmental Variable to ~/.bash_profile like so
JAVA_HOME=/usr/bin/java #or whatever your path is
export PATH=$PATH:$JAVA_HOME/bin/
You can open ~/.bash_profile in a terminal with nano
nano ~/.bash_profile.
Nano hint: writeout means save.
You'll need to reopen your terminal to load the new path. Or, reload it with the source command.
source ~/.bash_profile
Alternatively, if you like saving keystrokes you can type
. ~/.bash_profile