jdk-6u16-linux-i586-rpm.bin安裝後
修改 vi /etc/profile，添加下面
export JAVA_HOME=/usr/java/jdk1.6.0_16
export PATH=$PATH:$JAVA_HOME/bin:$JAVA_HOME/jre/bin
export CLASSPATH=.:$JAVA_HOME/lib:$JAVA_HOME/jre/lib:$CLASSPATH
. /etc/profile
[root@rhtx java]# java -version
java version "1.4.2"
gij (GNU libgcj) version 4.1.2 20080704 (Red Hat 4.1.2-46)
[root@rhtx java]# javac -version
javac 1.6.0_16
就是沒換過來，這裏用這個方法解決：
[root@rhtx java]# update-alternatives --install /usr/bin/java java /usr/java/jdk1.6.0_16/jre/bin/java 60
[root@rhtx java]# update-alternatives --config java
There are 2 programs which provide 'java'.
Selection Command
-----------------------------------------------
*+ 1 /usr/lib/jvm/jre-1.4.2-gcj/bin/java
2 /usr/java/jdk1.6.0_16/jre/bin/java
Enter to keep the current selection[+], or type selection number: 2
[root@rhtx java]# java -version
java version "1.6.0_16"
Java(TM) SE Runtime Environment (build 1.6.0_16-b01)
Java HotSpot(TM) Server VM (build 14.2-b01, mixed mode)
或者，應該可以通過刪除1.4的方法來解決：
[root@rhtx java]# rpm -qa|grep java
sun-javadb-docs-10.4.2-1.1
sun-javadb-core-10.4.2-1.1
java-1.4.2-gcj-compat-1.4.2.0-40jpp.115
sun-javadb-client-10.4.2-1.1
sun-javadb-demo-10.4.2-1.1
sun-javadb-common-10.4.2-1.1
sun-javadb-javadoc-10.4.2-1.1
把java-1.4.2 的刪除了，可以解決。