卸载之前的 jdk
[root@localhost ~]# rpm -qa|grep java
java-1.7.0-openjdk-headless-1.7.0.51-2.4.5.5.el7.x86_64
python-javapackages-3.4.1-5.el7.noarch
tzdata-java-2014b-1.el7.noarch
javapackages-tools-3.4.1-5.el7.noarch
java-1.7.0-openjdk-1.7.0.51-2.4.5.5.el7.x86_64
[root@localhost ~]# rpm -e --nodeps java-1.7.0-openjdk-headless-1.7.0.51-2.4.5.5.el7.x86_64
[root@localhost ~]# rpm -e --nodeps java-1.7.0-openjdk-1.7.0.51-2.4.5.5.el7.x86_64



测试环境 red Hat Linux 5.4

jdk版本 1.7/1.8

jdk下载地址：

http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

使用xftp工具将安装包传送到linux中
[root@linuxmain ~]# ls anaconda-ks.cfg  Desktop  install.log  install.log.syslog [root@linuxmain ~]# cd / 
[root@linuxmain /]# ls bin   dev  home  lost+found  misc  net  proc  sbin     srv  tmp  var boot  etc  lib   media       mnt   opt  root  selinux  sys  usr
[root@linuxmain /]# cd usr
[root@linuxmain usr]# ls bin    hadoop-2.5.1         java                     kerberos  local  src etc    hadoop-2.5.1.tar.gz  jdk-7u71-linux-i586.rpm  lib       sbin   tmp games  include              jdk-8u25-linux-i586.rpm  libexec   share  X11R6
[root@linuxmain usr]# rpm -ivh jdk-8u25-linux-i586.rpm  
开始安装 ... ...你将会看到如下的代码界面
[root@linuxmain usr]# rpm -ivh jdk-7u71-linux-i586.rpm Preparing...                ########################################### [100%]    1:jdk                    ########################################### [100%] Unpacking JAR files...         rt.jar...         jsse.jar...         charsets.jar...         tools.jar...         localedata.jar...         jfxrt.jar...         plugin.jar...         javaws.jar.
接下来配置环境变量其实环境变量不配置都可以用的但是还是配置上吧

[root@linuxmain ~]# vi .bashrc

# .bashrc

# User specific aliases and functions

alias rm='rm -i' alias cp='cp -i' alias mv='mv -i'

# Source global definitions if [ -f /etc/bashrc ]; then         . /etc/bashrc fi 
export JAVA_HOME=/usr/java/jdk1.7.0_71
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH                                                                         ~                                                                               ~                                                                               ~                                                                               ~                                                                               ~                                                                               ~                                                                               ".bashrc" 16L, 335C
输入字母i小写的进入编辑状态 完成之后 输入shift+: 输入wq! 保存退出
[root@linuxmain ~]# java -version java version "1.7.0_71" Java(TM) SE Runtime Environment (build 1.7.0_71-b14) Java HotSpot(TM) Client VM (build 24.71-b01, mixed mode, sharing) 
[root@linuxmain ~]#


代表你成功了可以简单的写个测试类测试一下