Install JDK installation steps under Linux using the installation package

Install the JDK installation steps under Linux using the installation package:
1. Download the tar.gz installation package
2. Unzip the installation package
3. Configuring the Environment
4. Modify the default settings
5. Whether the test was successful

1. Download:
You can use the URL of the wget (tar.gz installation package) or download it directly and copy it directly.
2. Unzip:
Tar package compression
-C Archive File
-X Compressed file
-Z gzip Compressed file
-V shows the compression or decompression process V (view)
-F Use file name

TAR-CVF/HOME/ABC.TAR/HOME/ABC only packaged, not compressed
TAR-ZCVF/HOME/ABC.TAR.GZ/HOME/ABC packaged and compressed with gzip

-ZXVF gzip Format extract display process generate file name
-XVF non-fixed format decompression display process generate file name
-CVF non-fixed format compression display process generated file name
-ZCVF gzip format compression display process generate file name

3. Configure the environment Vim ~/.BASHRC or modify the///program file???
Java_home = JDK installation directory
/usr/lib/jvm/(unzipped jdk) JDK
CLASSPATH = ClassLoader location (where bytecode files are stored) can have multiple, middle use: separate spaces
PATH = Execution file location of the compilation run (Java Javac, etc.)
Jre_home = location of the core jar package

E:

1 export java_home=/usr/lib/jvm/2 export jre_home=${java_home}/3 Export classpath=.:${java_home}/lib:${jre_home}/4 export path=${java_home}/bin: $PATH

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Execute the source ~/.BASHRC to complete the modification

4. Configure the default JDK version
For multiple versions, or JDK versions installed by default on the system

1 sudoUpdate-alternatives--Install/usr/bin/java Java/usr/lib/jvm/jdk8/bin/java - 2 sudoUpdate-alternatives--Install/usr/bin/javac Javac/usr/lib/jvm/jdk8/bin/javac - 3 sudoUpdate-alternatives--Install/usr/bin/jar Jar/usr/lib/jvm/jdk8/bin/jar - 4 sudoUpdate-alternatives--Install/usr/bin/javah Javah/usr/lib/jvm/jdk8/bin/javah - 5 sudoUpdate-alternatives--Install/USR/BIN/JAVAP JAVAP/USR/LIB/JVM/JDK8/BIN/JAVAP - 6 sudoUpdate-alternatives--config Java

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Performing an update displays the JDK that is already in the system and then selects one as the default

[Email protected]:~$ sudo update-alternatives--config java
There are 3 candidates that can be used to replace Java (providing/usr/bin/java).


Select Path Priority state
------------------------------------------------------------
* 0/usr/lib/jvm/java-6-openjdk/jre/bin/java 1061 Auto mode
1/usr/lib/jvm/java-6-openjdk/jre/bin/java 1061 Manual Mode
2/usr/lib/jvm/java-6-sun/jre/bin/java 63 Manual Mode
3/usr/lib/jvm/java-7-sun/bin/java 300 Manual Mode


To maintain the current value [*] press ENTER, or type the number of your choice: 3
Update-alternatives: Use/usr/lib/jvm/java-7-sun/bin/java to provide/usr/bin/java (Java) in manual mode.

5. Use Java-version to view

6.which Javac View the path to the default installation JDK

Install JDK installation steps under Linux using the installation package