How to install JDK8 binary on ubuntu14.10(64Bit)

軟體準備

• jdk-8u31-linux-x64.tar.gz

一、準備要放JDK的路徑

cd /usr/local

sudo mkdir java

二、將檔案解壓縮

cd /usr/local/java

sudo tar xzvf ~/Downloads/jdk-8u31-linux-x64.tar.gz

三、Ubuntu更新JDK8安裝位置

sudo update-alternatives --install "/usr/bin/java" "java" "/usr/local/java/jdk1.8.0_31/jre/bin/java" 1

sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/local/java/jdk1.8.0_31/bin/javac" 1

sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/local/java/jdk1.8.0_31/jre/bin/javaws" 1

sudo update-alternatives --set java /usr/local/java/jdk1.8.0_31/jre/bin/java

sudo update-alternatives --set javac /usr/local/java/jdk1.8.0_31/bin/javac

sudo update-alternatives --set javaws /usr/local/java/jdk1.8.0_31/jre/bin/javaws

查看路徑是否設定成功

cd /usr/bin

ls -ld java*

以下訊息：
lrwxrwxrwx 1 root root 22 Mar 31 20:41 java -> /etc/alternatives/java
lrwxrwxrwx 1 root root 23 Mar 31 20:42 javac -> /etc/alternatives/javac
lrwxrwxrwx 1 root root 24 Mar 31 20:42 javaws -> /etc/alternatives/javaws

cd /etc/alternatives

ls -ld java*

以下訊息：
lrwxrwxrwx 1 root root 40 Aug 29 18:18 java -> /usr/local/java/jdk1.8.0_20/jre/bin/java
lrwxrwxrwx 1 root root 37 Aug 29 18:18 javac -> /usr/local/java/jdk1.8.0_20/bin/javac
lrwxrwxrwx 1 root root 42 Aug 29 18:19 javaws -> /usr/local/java/jdk1.8.0_20/jre/bin/javaws

查看java版本與路徑

javac -version

java -version

which javac

which java

四、設定JAVA PATH跟JAVA HOME

cd /etc

sudo vim profile

export JAVA_HOME=/usr/local/java/jdk1.8.0_31
export PATH=$JAVA_HOME/bin:$PATH

儲存後離開

source /etc/profile

echo $JAVA_HOME

echo $PATH

參考鍵結：https://www3.ntu.edu.sg/home/ehchua/programming/howto/Ubuntu_HowTo.html#jdk