windows/linuxjdk安装,jdk1.6升级到1.7

一、JDK:

JAVA_HOME:

C:Program FilesJavajdk1.7.0_79

PATH:

;%JAVA_HOME%in;%JAVA_HOME%jrein

CLASSPATH:

 .;%JAVA_HOME%/lib/tools.jar;%JAVA_HOME%/lib/dt.jar;%JAVA_HOME%/jre/lib/rt.jar (注意开头的.和;)

MACOS:

/usr/bin/java指向/System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands/java,最终指向下边路径。

export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_112.jdk/Contents/Home

export PATH=$JAVA_HOME/bin:${PATH}

export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar

二、eclipse:

BuildPath: 当前jar包添加

lib:选择jre1.7,jdk1.7

No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?

解决办法:
  1、eclipse菜单 - Window - Preferences- Java - Installed JREs 将配置的JRE定位到JDK,例如JRE home:D:Program Files (x86)Javajdk1.6.0_45
  2、ALT+F5 进行 update project 。
  3、Debug or Run again.

二、linux

查看当前环境中安装了那些jdk,如果有那么卸载掉

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安装好的CentOS会自带OpenJdk,用命令 java -version ,会有下面的信息:
 java version "1.6.0"
OpenJDK  Runtime Environment (build 1.6.0-b09)
OpenJDK 64-Bit Server VM (build 1.6.0-b09, mixed mode)
 
最好还是先卸载掉openjdk,在安装sun公司的jdk. 
先查看 rpm -qa | grep java 
显示如下信息:
 java-1.4.2-gcj-compat-1.4.2.0-40jpp.115
java-1.6.0-openjdk-1.6.0.0-1.7.b09.el5
 
卸载: 
rpm -e --nodeps java-1.4.2-gcj-compat-1.4.2.0-40jpp.115
rpm -e --nodeps java-1.6.0-openjdk-1.6.0.0-1.7.b09.el5
 
还有一些其他的命令 
rpm -qa | grep gcj 
rpm -qa | grep jdk 
如果出现找不到openjdk source的话,那么还可以这样卸载
 
 yum -y remove java java-1.4.2-gcj-compat-1.4.2.0-40jpp.115
 yum -y remove java java-1.6.0-openjdk-1.6.0.0-1.7.b09.el5

安装jdk

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运行安装 
# rpm -ivh jdk-7u3-linux-x64.rpm
Preparing...                ########################################### [100%]
   1:jdk                    ########################################### [100%]
Unpacking JAR files...
    rt.jar...
    jsse.jar...
    charsets.jar...
    tools.jar...
    localedata.jar...
 
 # vim /etc/profile
修改profile 最后面加入 
export JAVA_HOME=/usr/java/jdk1.7.0_03
export CLASSPATH=.:$JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export PATH=$PATH:$JAVA_HOME/bin
 保存退出。运行 #source /etc/profile
 
之后 运行
# update-alternatives --install /usr/bin/java java /usr/java/jdk1.7.0_03/bin/java 60
# update-alternatives --config java
 你会看到我的ssh中存在乱码。
*+ 1           /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/java
   2           /usr/lib/jvm/jre-1.4.2-gcj/bin/java
   3           /usr/java/jdk1.7.0_03/bin/java
 输入3 敲回车
 然后一切ok
 
# java -version
java version "1.7.0_03"
Java(TM) SE Runtime Environment (build 1.7.0_03-b04)
Java HotSpot(TM) 64-Bit Server VM (build 22.1-b02, mixed mode)
原文地址:https://www.cnblogs.com/timssd/p/4738183.html