How to create non-editable JTable:

Override the method "isCellEditable" and implement as needed, such as:

//instance table model
DefaultTableModel tableModel = new DefaultTableModel(){
    @Override
    public boolean isCellEditable(int row, int column) {
        return false;
    }
};
//...other codes
table.setModel(tableModel);

System.getProperty(key) key list for Java with value:

java system get property, private link.

System.getProperty(key) key list for JAVA:

java.version	Java Runtime Environment version
java.vendor	Java Runtime Environment vendor
java.vendor.url	Java vendor URL
java.home	Java installation directory
java.vm.specification.version	Java Virtual Machine specification version
java.vm.specification.vendor	Java Virtual Machine specification vendor
java.vm.specification.name	Java Virtual Machine specification name
java.vm.version	Java Virtual Machine implementation version
java.vm.vendor	Java Virtual Machine implementation vendor
java.vm.name	Java Virtual Machine implementation name
java.specification.version	Java Runtime Environment specification version
java.specification.vendor	Java Runtime Environment specification vendor
java.specification.name	Java Runtime Environment specification name
java.class.version	Java class format version number
java.class.path	Java class path
java.library.path	List of paths to search when loading libraries
java.io.tmpdir	Default temp file path
java.compiler	Name of JIT compiler to use
java.ext.dirs	Path of extension directory or directories
os.name	Operating system name
os.arch	Operating system architecture
os.version	Operating system version
file.separator	File separator ("/" on UNIX)
path.separator	Path separator (":" on UNIX)
line.separator	Line separator ("\n" on UNIX)
user.name	User's account name
user.home	User's home directory
user.dir	User's current working directory

Download video from youtube in Ubuntu terminal

First download and install the program youtube-dl from terminal:

sudo apt-get install youtube-dl

After installation, you can download video from YouTube:

youtube-dl -o file_name.flv youtube-video-link

Sudoers - Community Ubuntu Documentation

Shutting Down From The Console Without A Password

Often people want to be able to shut their computers down without requiring a password to do so. This is particularly useful in media PCs where you want to be able to use the shutdown command in the media centre to shutdown the whole computer.

To do this you need to add some cmnd aliases as follows:

Cmnd_Alias SHUTDOWN_CMDS = /sbin/shutdown, /sbin/halt, /sbin/reboot

You also need to add a user specification (at the end of the file after the "%admin ALL = (ALL) ALL" line so it takes effect - see above for details):

ALL=(ALL) NOPASSWD: SHUTDOWN_CMDS

Obviously you need to replace "" with the username of the user who needs to be able to shutdown the pc without a password. You can use a user alias here as normal.

via Sudoers - Community Ubuntu Documentation.

FilePermissions

FilePermissions - Community Ubuntu Documentation.