查看目前系統的jdk: rpm -qa | grep jdk
得到的結果：
[root@dc-01 java]# rpm -qa | grep jdk
java-1.6.0-openjdk-1.6.0.0-1.45.1.11.1.el6.i686
卸載之：
[root@dc-01 java]# yum -y remove java-1.6.0-openjdk-1.6.0.0-1.45.1.11.1.el6.i686
等一段時間就Complete了。
下載Sun的JDK。我下載的是
jdk-6u37-linux-i586-rpm.bin
如果是64位系統的話，要下載：
jdk-6u37-linux-x64-rpm.bin
之類的64位專用的包
到/usr目錄下創建java目錄，將下載的文件放到/usr/java目錄下
先將這個文件變為可執行文件（chmod 777） ：
[root@dc-01 java]# chmod 777 jdk-6u37-linux-i586-rpm.bin
然后執行這個文件件進行安裝：
[root@dc-01 java]# ./jdk-6u37-linux-i586-rpm.bin
Unpacking...
Checksumming...
Extracting...
UnZipSFX 5.50 of 17 February 2002, by Info-ZIP (Zip-Bugs@lists.wku.edu).
inflating: jdk-6u37-linux-i586.rpm
inflating: sun-javadb-common-10.6.2-1.1.i386.rpm
inflating: sun-javadb-core-10.6.2-1.1.i386.rpm
inflating: sun-javadb-client-10.6.2-1.1.i386.rpm
inflating: sun-javadb-demo-10.6.2-1.1.i386.rpm
inflating: sun-javadb-docs-10.6.2-1.1.i386.rpm
inflating: sun-javadb-javadoc-10.6.2-1.1.i386.rpm
Preparing... ########################################### [100%]
1:jdk ########################################### [100%]
Unpacking JAR files...
rt.jar...
jsse.jar...
charsets.jar...
tools.jar...
localedata.jar...
plugin.jar...
javaws.jar...
deploy.jar...
Installing JavaDB
Preparing... ########################################### [100%]
1:sun-javadb-common ########################################### [ 17%]
2:sun-javadb-core ########################################### [ 33%]
3:sun-javadb-client ########################################### [ 50%]
4:sun-javadb-demo ########################################### [ 67%]
5:sun-javadb-docs ########################################### [ 83%]
6:sun-javadb-javadoc ########################################### [100%]
Java(TM) SE Development Kit 6 successfully installed.
Product Registration is FREE and includes many benefits:
* Notification of new versions, patches, and updates
* Special offers on Oracle products, services and training
* Access to early releases and documentation
Product and system data will be collected. If your configuration
supports a browser, the JDK Product Registration form will
be presented. If you do not register, none of this information
will be saved. You may also register your JDK later by
opening the register.html file (located in the JDK installation
directory) in a browser.
For more information on what data Registration collects and
how it is managed and used, see:
http://java.sun.com/javase/registration/JDKRegistrationPrivacy.html
Press Enter to continue.....
這個時候按一下回車。
出現Done .
至此安裝結束。
接下來配置JDK：
vi /etc/profile打開profile文件，在profile文件的末尾加上：
JAVA_HOME=/usr/java/jdk1.6.0_37
PATH=$JAVA_HOME/bin:$PATH
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export JAVA_HOME
export PATH
export CLASSPATH
保存並關閉profile文件，執行source /etc/profile命令讓修改生效。
運行下java-version 看一下java版本 ：
[root@dc-01 java]# java -version
java version "1.6.0_37"
Java(TM) SE Runtime Environment (build 1.6.0_37-b06)
Java HotSpot(TM) Client VM (build 20.12-b01, mixed mode, sharing)
[root@dc-01 java]#
================================================
至此，整個安裝過程完畢。