Installing JDK under Linux

First step: Check if the Linux-brought JDK is installed (uninstall CentOS installed 1.4)

The installed CentOS will bring openjdk, with the command java-version, will have the following information:

Java Version "1.6.0"
OpenJDK Runtime Environment (build 1.6.0-b09)
OpenJDK 64-bit Server VM (build 1.6.0-b09, Mixed mode)

It is best to uninstall the OPENJDK before installing Sun's JDK.

See Rpm-qa First | grep java

The following information is displayed:

java-1.4.2-gcj-compat-1.4.2.0-40jpp.115
Java-1.6.0-openjdk-1.6.0.0-1.7.b09.el5

Unloading:

RPM-E--nodeps java-1.4.2-gcj-compat-1.4.2.0-40jpp.115
RPM-E--nodeps Java-1.6.0-openjdk-1.6.0.0-1.7.b09.el5

There are some other commands.

Rpm-qa | grep GCJ

Rpm-qa | grep JDK

If OpenJDK source cannot be found, you can also uninstall this

Yum-y Remove Java java-1.4.2-gcj-compat-1.4.2.0-40jpp.115
Yum-y Remove Java Java-1.6.0-openjdk-1.6.0.0-1.7.b09.el5

<1># rpm-qa|grep jdk← View JDK information or execute directly
Or
# rpm-q JDK
Or
# java-version
<2># Rpm-qa | grep gcj← Confirm version number of GCJ
<3># yum-y Remove java-1.4.2-gcj-compat← Uninstall GCJ

Step Two: Install the JDK
<1> download Jdk-1_5_0_14-linux-i586-rpm.bin or Jdk-1_5_0_14-linux-i586.bin from Sun
Create a new Java folder under/usr and place the installation package in the/usr/java directory
# Mkdir/usr/java
<2> Installing the JDK
# Cd/usr/java
①jdk-1_5_0_14-linux-i586-rpm.bin File Installation
# chmod 777 jdk-1_5_0_14-linux-i586-rpm.bin← modified to executable
#./jdk-1_5_0_14-linux-i586-rpm.bin← Select Yes to agree to the above agreement
# RPM-IVH jdk-1_5_0_14-linux-i586.rpm← Select Yes until installation is complete
②jdk-1_5_0_14-linux-i586.bin File Installation
# chmod a+x jdk-1_5_0_14-linux-i586.bin← enables the current user to have Execute permissions
#./jdk-1_5_0_14-linux-i586.bin← Select Yes until installation is complete

Step Three: Configure environment variables
<1># Vi/etc/profile
<2> Add the following lines at the end:
Export JAVA_HOME=/USR/JAVA/JDK1.6.0_10
Export classpath=.: $JAVA _home/jre/lib/rt.jar: $JAVA _home/lib/dt.jar: $JAVA _home/lib/tools.jar
Export path= $PATH: $JAVA _home/bin
<3># reboot← Restart machine configuration effective

The CentOS version of this article is 5.4 final, using a graphical interface and commands in conjunction with the operation mode

Because CentOS 5.4 installs software such as OpenOffice by default, which requires Java support, a JDK environment is installed by default, and if a specific Java environment is required, it is best to uninstall or completely remove the default installed JDK.

After installing CentOS 5.4, enter "Java-version" directly in the terminal and the system will display the current JDK version number "Java-1.6.0-openjdk-1.6.0.0-1.7.b09.el5". You can see that the JDK is using the openjdk1.6 version.

If at this time, directly in the CentOS "application-Add/Remove Software-basic system--java", the removal of Java, and related to the OpenOffice and other software, will be automatically deleted, so before the original JDK delete, It is a good idea to install the new JDK and the appropriate environment first.

First, in the Sun (now Oracle) Web site Download the appropriate JDK version, here is the latest version of the JDK6.0_UPDATE21, when downloading, it is recommended to download the-rpm installation files, the download completed files in the specified location, here directly under/usr. The default download of the JDK file name is longer, you can modify the file name as needed, this is changed to "Jdk-6u21.bin".

Next, open the terminal in the directory where the JDK is located, give the current user the Execute permission, "chmod +x jdk-6u21.bin", or right-click the file directly under the GUI, select "Properties" in the pop-up menu, "Permissions", select "Execute File by program" check box, "OK" button, Completes the grant of the EXECUTE permission.

Then, open the terminal in the directory where the JDK is located, and enter "./jdk-6u21.bin" in the terminal to perform the decompression and installation operation. At this point, in the "/usr" directory, add a "/java" directory, in addition, there will be "sun" in the beginning of the RPM files, these files do not bother.

Next, set the environment variables for Java. （

Another type of:

2. Check uninstall the default JDK that is already installed

   [Email protected] ~]# Rpm-qa | grep JDK

   java-1.6.0-openjdk-1.6.0.0-1.45.1.11.1.el6.i68

   [Email protected] ~]# yum-y Remove java-1.6.0-openjdk-1.6.0.0-1.45.1.11.1.el6.i686

4. Installing the JDK into the/usr/java/jdk.xxx directory

   Create Directory Mkdir/usr/java

   Upload jdk-8u65-linux-i586.tar.gz to/usr/java

   Perform decompression tar-zxvf jdk-8u65-linux-i586.tar.gz under/usr/java, and view after decompression

6. Configuration environment variables, this is a reliable approach, the internet is all said to change the profile file, in fact, the CentOS profile inside the note file has been written, not recommended to modify this file, but in the PROFILE.D under the new user's own configuration file, so that the same can be effective.

8. [email protected] profile.d]# Touch jdk.sh

   [Email protected] profile.d]# VI jdk.sh

   Add the following to the jdk.sh file:

   Export java_home=/usr/java/jdk1.8.0_65

   Export path= $JAVA _home/bin: $PATH

   Export classpath=.: $JAVA _home/lib/dt.jar: $JAVA _home/lib/tools.jar

   After saving, then execute the following command:

   [Email protected] profile.d]# Source/etc/profile

10. 6

    [Email protected] profile.d]# java-version

    Java Version "1.8.0_65"

    Java (TM) SE Runtime Environment (build 1.8.0_65-b17)

    Java HotSpot (TM) Server VM (build 25.65-b01, Mixed mode)

）

Another type of:

Use a text editor to open/etc/profile (description: The/etc/directory under the root directory, where the profile file)
? Add the following string at the end of the profile file
Java_home=/usr/java/jdk1.6.0_21
Path= $JAVA _home/bin: $PATH
Classpath=.: $JAVA _home/lib/dt.jar: $JAVA _home/lib/tools.jar
Export Java_home
Export PATH
Export CLASSPATH
At this point, the new JDK environment installation configuration is complete.

Next, delete the original JDK environment.

First, enter "Rpm-qa|grep GCJ" in the terminal to see the version number of the GCJ, the result here is:

java-1.4.2-gcj-compat-1.4.2.0-40jpp.115
Libgcj-4.1.2-48.el5

Second, the uninstallation system comes with a JDK. Enter "Yum-y remove Java java-1.4.2-gcj-compat-1.4.2.0-40jpp.115" in the terminal and wait for the system to unload its own JDK. Finally, "complete!" is displayed in the terminal and the uninstallation is complete.

At this point, the JDK configuration on CentOS is basically complete, rebooting the system.

Input java-version error occurred:

/lib/ld-linux.so.2:bad ELF interpreter How to solve, here I analyze there are two, one is commonly used installation because of the system software bit problems, such as: 64-bit system installed 32-bit programs,

Problem one, 32-bit program resolution is installed on 64-bit systems

is because a 32-bit program is installed in a 64-bit system

Install this file:

Yum Install glibc.i686

（）

Enter "Java-version" in the terminal, the system displays:

Java Version "1.6.0_21"
Java (TM) SE Runtime Environment (build 1.6.0_21-b06)
Java HotSpot (TM) Client VMs (build 17.0-b16, mixed mode, sharing)

JDK installed successfully!

Installing JDK under Linux