如何替换掉系统默认的Java

SeAL80s

        系统Fedora 23 x86_64 xfce4.12

        ls -l /usr/bin/java
lrwxrwxrwx 1 root root 22 Jan 27 12:01 /usr/bin/java -> /etc/alternatives/java

➜  ~  ls -l /etc/alternatives/java
lrwxrwxrwx 1 root root 71 Jan 27 12:01 /etc/alternatives/java -> /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/java
➜  ~  ls -l /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/java

-rwxr-xr-x 1 root root 7336 Jan 20 22:00 /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/java

       系统在执行任何依赖Java的应用的时候,都会调用系统默认的Java.比如IDEA/Eclipse , 启动时,在task里都会有两个java在运行.
     如果是在shell里执行/opt/ideaIC/bin/idea.sh,那么回执行自定义的Java (/opt/jdk1.8.0_72),不过在面板里执行.desktop文件,首先要调用系统默认的Java,所以才导致进程里有两个不同的Java.现在想知道,能不能把系统级的java,设置为我的字设定的/opt/jdk1.8.0_72 ?

        

剑魂箫心

yum卸了他再装jdk官方版

SeAL80s

回复 2# 剑魂箫心


    不管用的.而且Eclipse/IDEA启动要去找/usr/bin/java.光做链接只能暂时解决问题.其他的需要OpenJDK的项目,还是要装OpenJDK.

    我的意思是,告诉系统,我已经有JDK了,目录就在/opt/jdk1.8.0_72.不需要openjdk.需要java的,去$JAVA_HOME找...


    update-alternatives 只发现系统里有openjdk.我编辑了/etc/profile,添加$JAVA_HOME也不管用...

剑魂箫心

回复 3# SeAL80s


    JRE_HOME、PATH、CLASSPATH这些变量都正确设置了吗

SeAL80s

回复 4# 剑魂箫心


    都设置了.但是觉得通知系统/opt/jdk 在哪好像不止这几个变量,还有其他的操作不清楚.

    update-alternatives --list | grep java
java_sdk_openjdk        auto        /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64
jaxp_parser_impl        auto        /usr/share/java/xerces-j2.jar
java        auto        /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/java
java_sdk_1.8.0_openjdk        auto        /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64
jre_1.8.0        auto        /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre
libjavaplugin.so.x86_64        auto        /usr/lib64/IcedTeaPlugin.so
jaxp_transform_impl        auto        /usr/share/java/xalan-j2.jar
java_sdk_1.8.0        auto        /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64
javac        auto        /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/bin/javac
jre_openjdk        auto        /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre
➜  
有这么多变量.有时间我去找找Fedora对于OpenJDK的设置吧,看看Linux是如何支持Java的,或许能有点眉目.
Linux支持官方的JDK,而且我根本不用OpenJDK .系统里本来有自己用的官方JDK,其他依赖工具还要装一堆openjdk,太不爽了...不过,这个不算大问题,有时间慢慢找吧...
多谢!

SeAL80s

回复 5# SeAL80s


    fedoraproject.org/wiki/Java#Java_Runtime_Environments_.28JRE.29

    linuxbsdos.com/2014/09/19/how-to-install-oracle-jre-on-fedora-20-and-use-alternatives-to-switch-between-it-and-openjdk

    但是还是没解释,其他软件如何用用户自定义的JAVA.

    如果sudo dnf remove openjdk,还是会卸载有相关依赖的软件.

    vim /etc/java/java.conf

    发现几个系统级别的变量和路径,也改了

    # System-wide Java configuration file  -*- sh -*-

# Location of jar files on the system
JAVA_LIBDIR=/usr/share/java

# Location of arch-specific jar files on the system
JNI_LIBDIR=/usr/lib/java

# Root of all JVM installations
#JVM_ROOT=/usr/lib/jvm

JVM_ROOT=/opt/jdk1.8.0_72
# You can define a system-wide JVM root here if you're not using the
# default one.
#
# If you have a base JRE package installed
# (e.g. java-1.6.0-openjdk):
JAVA_HOME=$JVM_ROOT/jre
#
# If you have a devel JDK package installed
# (e.g. java-1.6.0-openjdk-devel):
#JAVA_HOME=$JVM_ROOT/java

JAVA_HOME=$JVM_ROOT/bin/java
# Options to pass to the java interpreter
#JAVACMD_OPTS=

# You can disable ABRT Java Connector by setting JAVA_ABRT to "off".
# See: https://github.com/jfilak/abrt-java-connector/
JAVA_ABRT=off

另外
~  alternatives --display java
java - status is manual.
link currently points to /opt/jdk1.8.0_72/bin/java
/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/java - family java-1.8.0-openjdk priority 1800071
slave jjs: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/jjs
slave keytool: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/keytool
slave orbd: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/orbd
slave pack200: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/pack200
slave policytool: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/policytool
slave rmid: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/rmid
slave rmiregistry: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/rmiregistry
slave servertool: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/servertool
slave tnameserv: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/tnameserv
slave unpack200: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre/bin/unpack200
slave jre_exports: /usr/lib/jvm-exports/jre-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64
slave jre: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64/jre
slave java.1.gz: /usr/share/man/man1/java-java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64.1.gz
slave jjs.1.gz: /usr/share/man/man1/jjs-java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64.1.gz
slave keytool.1.gz: /usr/share/man/man1/keytool-java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64.1.gz
slave orbd.1.gz: /usr/share/man/man1/orbd-java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64.1.gz
slave pack200.1.gz: /usr/share/man/man1/pack200-java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64.1.gz
slave policytool.1.gz: /usr/share/man/man1/policytool-java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64.1.gz
slave rmid.1.gz: /usr/share/man/man1/rmid-java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64.1.gz
slave rmiregistry.1.gz: /usr/share/man/man1/rmiregistry-java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64.1.gz
slave servertool.1.gz: /usr/share/man/man1/servertool-java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64.1.gz
slave tnameserv.1.gz: /usr/share/man/man1/tnameserv-java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64.1.gz
slave unpack200.1.gz: /usr/share/man/man1/unpack200-java-1.8.0-openjdk-1.8.0.71-1.b15.fc23.x86_64.1.gz
/opt/jdk1.8.0_72/bin/java - priority 18000072
slave jjs: (null)
slave keytool: (null)
slave orbd: (null)
slave pack200: (null)
slave policytool: (null)
slave rmid: (null)
slave rmiregistry: (null)
slave servertool: (null)
slave tnameserv: (null)
slave unpack200: (null)
slave jre_exports: (null)
slave jre: (null)
slave java.1.gz: (null)
slave jjs.1.gz: (null)
slave keytool.1.gz: (null)
slave orbd.1.gz: (null)
slave pack200.1.gz: (null)
slave policytool.1.gz: (null)
slave rmid.1.gz: (null)
slave rmiregistry.1.gz: (null)
slave servertool.1.gz: (null)
slave tnameserv.1.gz: (null)
slave unpack200.1.gz: (null)
Current `best' version is /opt/jdk1.8.0_72/bin/java.
看到输出了,还有些null需要解决

改了/etc/可能是要重启才能生效吧.今天有点累了,思路有点模糊了...