Getting the JDK

On Ubuntu/Debian

$ sudo apt install openjdk-8-jre

On Fedora/CentOS:

$ su - "yum install java-1.8.0-openjdk"

On Windows, visit

Install Eclipse

  • download from
  • extract files from the eclipse-inst-(platform).tar.gz file.
  • into the eclipse-installer folder run the eclipse-inst file.
  • check for the advanced mode if you want to tune your eclipse installation.

Set default Java version (linux)

Use the command alternatives:

$ sudo alternatives --config java
[sudo] password for user:
There are 3 programs which provide 'java'.

  Selection    Command
   1           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-
   2           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-
*+ 3           java-9-openjdk.x86_64 (/usr/lib/jvm/java-9-openjdk-
Enter to keep the current selection[+], or type selection number:

and choose the version you need.

The java command options

# to launch a class file:
java [options] mainclass [args ...]

# to launch a mainclass in a JAR file:
java [options] -jar jarfile [args ...]

# to launch the main class in a module:
java [options] -m module[/mainclass] [args ...]
# or
 --module module[/mainclass] [args ...]

# to launch a single source-file program:
java [options] source-file [args ...]


    Sets a system property value. The property variable is a string with no spaces that
    represents the name of the property. The value variable is a string that represents
    the value of the property. If value is a string with spaces, then enclose it in
    quotation marks
    (example -Dfile.encoding=UTF8

-Xmx size
    Specifies the maximum size (in bytes) of the heap. This value must be a multiple of
    1024 and greater than 2 MB. Append the letter k or K to indicate kilobytes, m or M
    to indicate megabytes, or g or G to indicate gigabytes. The default value is chosen
    at runtime based on system configuration. For server deployments, -Xms and -Xmx
    are often set to the same value. The following examples show how to set the
    maximum allowed size of allocated memory to 80 MB using various units:


-Xss size
    Sets the thread stack size (in bytes). Append the letter k or K to indicate KB, m
    or M to indicate MB, or g or G to indicate GB. The default value depends on the

    - Linux/x64 (64-bit): 1024 KB
    - macOS (64-bit): 1024 KB
    - Oracle Solaris (64-bit): 1024 KB
    - Windows: The default value depends on virtual memory

    The following examples set the thread stack size to 1024 KB in different units:

Advanced Garbage Collection Options for Java: