Java升级替换java version "1.5.0"

首先进行java安装

http://www.cnblogs.com/someone9/p/8670585.html

2. 然后查看版本信息，仍然是1.5.0

[root@OKC java]# java -version
java version "1.5.0"
gij (GNU libgcj) version 4.4.7 20120313 (Red Hat 4.4.7-18)

Copyright (C) 2007 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 3.然后执行

[root@OKC ~]# alternatives --install /usr/bin/java java /usr/java/jdk1.8.0_161/bin/ 300
appletviewer    javac           javaws          jinfo           jsadebugd       orbd            serialver
ControlPanel    javadoc         jcmd            jjs             jstack          pack200         servertool
extcheck        javafxpackager  jconsole        jmap            jstat           policytool      tnameserv
idlj            javah           jcontrol        jmc             jstatd          rmic            unpack200
jar             javap           jdb             jmc.ini         jvisualvm       rmid            wsgen
jarsigner       javapackager    jdeps           jps             keytool         rmiregistry     wsimport
java            java-rmi.cgi    jhat            jrunscript      native2ascii    schemagen       xjc

 4.进行选择配置 填写 3 .我们刚配置的环境

[root@OKC ~]# alternatives --config java

There are 3 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
*  1           /usr/lib/jvm/jre-1.5.0-gcj/bin/java
 + 2           /usr/bin/java/jdk1.8.0_161/bin/java
   3           /usr/java/jdk1.8.0_161/bin/java

Enter to keep the current selection[+], or type selection number: 3

 5.再次查看版本信息

[root@OKC ~]# java -version
java version "1.8.0_161"
Java(TM) SE Runtime Environment (build 1.8.0_161-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.161-b12, mixed mode)

 注：

假若第三步所配置的不是我们安装的位置，或者超出目录范围将会报错

-bash: /usr/bin/java: Too many levels of symbolic links
按照上面第三步重新配置即可

[root@OKC java]# alternatives --install /usr/bin/java java /usr/bin/java/jdk1.8.0_161/bin/java 300
[root@OKC java]# java -version
java version "1.5.0"
gij (GNU libgcj) version 4.4.7 20120313 (Red Hat 4.4.7-18)

Copyright (C) 2007 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
[root@OKC java]# alternatives --config java

There are 2 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
*+ 1           /usr/lib/jvm/jre-1.5.0-gcj/bin/java
   2           /usr/bin/java/jdk1.8.0_161/bin/java

Enter to keep the current selection[+], or type selection number: 2
[root@OKC java]# java -version
-bash: /usr/bin/java: Too many levels of symbolic links