Practical Operation Log: Install JDK in Linux

Ten years later, computers are becoming more and more popular. Many people have been applying computers, and the most essential part of the computer is the operating system. We often see Microsoft and Linux. However, Linux is developing very rapidly and is catching up with Microsoft. Here we will introduce the knowledge of Linux, so that you can learn how to use Linux. Today I will talk about installing JDK in Linux to configure environment variables. I hope you will remember to install JDK in Linux to configure environment variables.

1. Go to the http://java.sun.com/j2se/1.4.2/download.html to download a Linux Platform JDK, it is recommended to download RPM self-extract format RPM in self-extracting file, j2sdk-1_4_2_06-linux-i586-rpm.bin );

2. Upload the file to a Linux server and run the following command in shell:

 
 

  
  
[root@LinuxServer rpm]# chmod 755 j2sdk-1_4_2_06-linux-i586-rpm.bin  
  
  
[root@LinuxServer rpm]# ./j2sdk-1_4_2_06-linux-i586-rpm.bin  
 
 

There will be a piece of Sun Protocol, several times the Space key, when asked whether to agree, you can press yes.

 
 

  
  
Sun Microsystems, Inc.  
  
  
Binary Code License Agreement  
  
  
for the  
  
  
JAVATM 2 SOFTWARE DEVELOPMENT KIT (J2SDK), STANDARD  
  
  
EDITION, VERSION 1.4.2_X  
  
  
…  
  
  
Do you agree to the above license terms? [yes or no]yes  
  
  
Unpacking...  
  
  
Checksumming...  
  
  
0  
  
  
0  
  
  
Extracting...  
  
  
UnZipSFX 5.40 of 28 November 1998, by Info-ZIP (Zip-Bugs@lists.wku.edu).  
  
  
inflating: j2sdk-1_4_2_06-linux-i586.rpm    
  
  
Done.  
 
 

3. The program will automatically generate a j2sdk-1_4_2_06-linux-i586.rpm file, which is the main package, to install below;

 
 

  
  
[root@LinuxServer rpm]#rpm –ivh j2sdk-1_4_2_06-linux-i586.rpm  
  
  
Preparing...                ########################################### [100%]  
  
  
1:j2sdk                ########################################### [100%]  
 
 

4. Set Environment Variables
Usually, you prefer to use the export command to directly set it in shell.

 
 

  
  
[root@LinuxServer rpm]# export JAVA_HOME=/usr/java/j2sdk1.4.2_06  
  
  
[root@LinuxServer rpm]# export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar  
  
  
[root@LinuxServer rpm]# export PATH=$PATH:$JAVA_HOME/bin  
 
 

Of course, this setting of environment variables takes effect only for the current shell. If you log on from another shell, you cannot use the variable you just set. So the best way is to modify the. bashrc file.

 
 

  
  
[root@LinuxServer rpm]#vi .bashrc  
  
  
set JAVA_HOME=/usr/java/j2sdk1.4.2_06  
  
  
export JAVA_HOME  
  
  
set PATH=$PATH:$JAVA_HOME/bin  
  
  
export PATH  
  
  
set CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar  
  
  
export CLASSPATH   
 
 

Of course, you can also change the/etc/profile. However, this setting is not recommended because it will take effect for your shell and affect system security. Next, we will verify whether the variable settings take effect. Before verification, we will log out and then log on again );

 
 

  
  
[root@LinuxServer rpm]# echo $JAVA_HOME  
  
  
/usr/java/j2sdk1.4.2_06/  
  
  
[root@LinuxServer rpm]# echo $CLASSPATH  
  
  
/usr/java/j2sdk1.4.2_06/lib/dt.jar:/usr/java/j2sdk1.4.2_06/lib/tools.jar  
  
  
[root@LinuxServer rpm]# echo $PATH  
  
  
/usr/java/j2sdk1.4.2_06/bin/:/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/X11R6/bin:/root/bin  
  
  
[root@LinuxServer rpm]# -version  
  
  
JAVA version "1.4.2_06"  
  
  
JAVA(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_06-b03)  
  
  
JAVA HotSpot(TM) Client VM (build 1.4.2_06-b03, mixed mode)JAVA  
 
 

5. Set the environment to OK to see if JDK works normally. Let's write a test file test. java.

 
 

  
  
[root@LinuxServer rpm]#vi test.java  
  
  
class test   
  
  
{  
  
  
        public static void main(String[] args)   
  
  
        {  
  
  
               System.out.println("Hello World!");  
  
  
        }  
  
  
}  
 
 

Save and exit. Compile and execute the command below;

 
 

  
  
[root@LinuxServer text]# javac test.java  
  
  
[root@LinuxServer text]# test  
  
  
Hello World!JAVA  
 
 

OK. The operation is normal.

6. To allow a user to run java commands, modify the bash initialization file.
For example, to grant longware the permission to run java commands,

 
 

  
  
[root@LinuxServer root]# vi /home/longware/.bashrc  
  
  
set JAVA_HOME=/usr/java/j2sdk1.4.2_06  
  
  
export JAVA_HOME  
  
  
set PATH=$PATH:$JAVA_HOME/bin  
  
  
export PATH  
  
  
set CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar  
  
  
export CLASSPATH  
 
 

7. Now, JDK installation on Linux is complete. This completes the installation of JDK environment variables in Linux.

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