linux下安裝jdk1.6版本顯示1.4，修改默認jdk版本

當成功把jdk1.6安裝到 /usr/java，並且配置好了系統環境變量 

 

執行 # java -version 時顯示的不是你安裝的jdk版本，而是其它版本如jdk1.4.2，是因爲linux系統有默認的jdk，版本爲1.4.2;

 

[root@ip-10-0-0-54 lib]# java -version
java version "1.4.2"
gij (GNU libgcj) version 4.1.2 20080704 (Red Hat 4.1.2-44)

Copyright (C) 2006 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@ip-10-0-0-54 lib]# java -version
java version "1.4.2"
gij (GNU libgcj) version 4.1.2 20080704 (Red Hat 4.1.2-44)
Copyright (C) 2006 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.

 

 

 

切換默認jdk版本執行

1. 

 

# cd /usr/bin
# ln -s -f /usr/java/jdk1.6.0_24/jre/bin/java
# ln -s -f /usr/java/jdk1.6.0_24/bin/javac

# cd /usr/bin 
# ln -s -f /usr/java/jdk1.6.0_24/jre/bin/java 
# ln -s -f /usr/java/jdk1.6.0_24/bin/javac 

 

2. Remove the old empty java environment 

# rm -f /usr/bin/java
# rm -f /usr/bin/javac
# rm -f /etc/alternatives/java
# rm -f /etc/alternatives/javac）

# rm -f /usr/bin/java 
# rm -f /usr/bin/javac 
# rm -f /etc/alternatives/java 
# rm -f /etc/alternatives/javac） 

 

如果執行完1，查看 /usr/bin下的java properties，如果已經修改過來了，則步驟2不必再執行，命令行輸入 

# java –version 

則可以看到jdk版本已經正常

java version "1.6.0_24"
Java(TM) SE Runtime Environment (build 1.6.0_24-b07)
Java HotSpot(TM) 64-Bit Server VM (build 19.1-b02, mixed mode)