How to create a new folder from a terminal with administrative permissions?

Create the folder from a command line terminal using:

sudo mkdir /usr/java

You need sudo to make changes to /usr because /usr is owned by the root user.

I'm going to address two parts of your question: java installation and folder creation.

Java installation

We already have a question about that: How can I install Sun/Oracle's proprietary Java JDK 6/7/8 or JRE?.All of the necessary commands are there, and I strongly suggest you read their manual pages with man COMMAND in terminal.

There's also open-source version of Java, Open JDK. Installation of that is somewhat simpler

sudo apt-get install openjdk-7-jre openjdk-7-jdk icedtea-7-plugin

That's pretty much it - apt-get will take care of everything. When you install some package with apt-get or dpkg there should be preinstall and postinstall scripts that come along with the package, and run automatically to set up whatever program you're getting.

Folder Creation

Folder ( in linux terminology - directory ) creation, just like file creation, depends on the permissions. If a folder has the following permissions,

drwxr-xr-x 15 testuser  testuser   4096 Nov 22 12:34 testuser/

that means the owner of that folder testuser can read-write-execute stuff there (first rwx), and group testuser can only read and execute stuff there - that's the r-x part, and final r-x part means read execute for any other groups or users.

/usr folder is owned by root user, so only root can write there, that means create files or folder. Hence for that you need sudo to gain root privileges temporarily.

You have a few choices:

• gksudo pcmanfm will request you enter your password, then open PCManFM as root, which is somewhat dangerous because if you are not careful you may unintentionally modify system files.

• sudo mkdir /usr/java will create the directory directly.