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Java

Development (8) Manual (5)
Konrad Twardowski

This documentation is obsolete

Java

JRE (Java Runtime Environment)

  • Allows you to run Java applications

JDK (Java Development Kit)

  • Includes JRE, compiler, and other development tools
  • Install JDK if want to compile *.java source files or use Makagiga [SDK]

Tips

Makagiga packages with private Java JRE included (5.x)

Private JRE will be used by Makagiga only and it will not affect your system. You can always remove the private JRE (java-linux-i586 or java-windows-i586 directory) to switch to your default system Java.

The following packages include Java:

  • makagiga-*.exe (installer for Windows)
  • makagiga-linux-i586-*.7z

General

Linux

Private Java JRE

If you don't want to install Java on your system you can try makagiga-linux-i586-*.7z package with Java 8 already included. See above Tips for more details.

Automatic Java 8 Installation via APT (Ubuntu, etc.)

See http://www.webupd8.org/2012/09/install-oracle-java-8-in-ubuntu-via-ppa.html

Automatic Java 7 Installation via APT (Ubuntu, etc.)

  1. Run "sudo apt-get install openjdk-7-jre"
  2. Run "java -version" to verify installation
  3. It should print something like this: java version "1.7.0...

Note: If you have more than one Java version installed, you should also run
"sudo update-alternatives --config java"
to select the default "java" program.

Manual Java Installation (1/3)

This is a generic tutorial and should work with all Linux distributions...

  1. Download the latest *.tar.gz
  2. Run "tar -xzf YOUR_VERSION.tar.gz" to unpack downloaded archive

You can unpack this archive into any preferred location (e.g. /opt/java)

Manual Java Installation (2/3)

Modify system settings to set the default "java" launcher.

  1. Set the JAVA_HOME environment variable:
    • Add export JAVA_HOME=/opt/java/jre1.8.0 line to your ~/.profile or /etc/profile file
  2. Set the PATH environment variable:
    • Add export PATH=/opt/java/jre1.8.0/bin:$PATH line to your ~/.profile or /etc/profile file
  3. Create symbolic link (optionally):
    • Run: ln -s /opt/java/jre1.8.0/bin/java /usr/bin

Manual Java Installation (3/3)

Now you can run "java -version" to verify the previous installation steps.

Make sure all the paths in $PATH are correct.

Common Problems

Exception in thread "main" java.lang.UnsupportedClassVersionError: org/makagiga/Main : Unsupported major.minor version 52.0

You are using Java 7 (or older) to launch an application that requires Java 8+.

Makagiga 5.x requires Java 8 or newer.

Exception in thread "main" java.lang.UnsupportedClassVersionError (...) : Unsupported major.minor version 51.0

You are using Java 6 (or older) to launch an application that requires Java 7+.

Makagiga 4.x requires Java 7 or newer.

Ant build tool does not work

  • Make sure Ant is installed and setup correctly.
    • Tip: Use WinAnt to install Ant on Windows
  • Make sure the Java JDK is installed correctly.
  • If necessary set JAVA_HOME environment variable to your JDK installation directory.
    • Windows: Control Panel -> System -> Advanced -> Environment Variables
    • ...or reinstall WinAnt

Related

Wiki: SDK