How to install Oracle Java 12 on Ubuntu

See https://www.linuxuprising.com/2019/03/how-to-install-oracle-java-12-jdk-12-in.html Simply put, open a terminal window and enter following commands: $ sudo add-apt-repository ppa:linuxuprising/java <enter> $ sudo apt update <enter> $ sudo apt install oracle-java12-installer <enter> After the installation is complete, you can verify that the Java plugin has been installed by starting your Firefox web browser and typing about:plugins in the URL … Continue reading How to install Oracle Java 12 on Ubuntu

How to fix Eclipse Tab Size, Spacing between menu options and more in Xubuntu 16.04 LTS

Using Numix as the theme on Xubuntu 16.04 LTS, we find that Eclipse IDE toolbars, fonts, menus have excessive spaces between them. They look too big and take away screen real estate forcing you to scroll more. If you change the Settings -> Appearance to Greybird and Settings -> Window Manager to Daloa or something … Continue reading How to fix Eclipse Tab Size, Spacing between menu options and more in Xubuntu 16.04 LTS

How to code multiple line tooltips with bold text

Many Java programs use tool tips in Java Swing to display more information when the mouse cursor hovers over a button or text field. There is a method of making text within that tool tip bold, italics, colored and more. Below is an illustration of the command that uses HTML tags to display that formatting … Continue reading How to code multiple line tooltips with bold text

How to close the program in Java completely in Swing

A Java Swing application can be closed using the following code segment to retrieve the parent of the container, check if it is a JFrame and then dispose the JFrame: public class btnCancelListener implements ActionListener { public void actionPerformed(ActionEvent ev) { Container bframe = btnCancel.getParent(); bframe = bframe.getParent(); while (! (bframe instanceof JFrame)) { System.out.println("Done"); … Continue reading How to close the program in Java completely in Swing

How to disable File Name Input in JFileChooser in Java

JFileChooser is a very powerful Component in Java. It even enables filtering of file names. However, there is no direct method to prevent a user from entering the File Name input in it. The following method disables the JTextField File input text box in  JFileChooser, by basically taking the JFileChooser as a Component, looking for … Continue reading How to disable File Name Input in JFileChooser in Java

Error building Java Program in Eclipse Mars after changing Java version

Right Click on the Project in the Package Explorer. Select Build Path -> Configure Build Path -> Libraries. Now remove JRE System Library 1.7 and add the one for java-8-oracle by clicking on Add Library -> JRE System Library -> Click Execution Environment and set that to JavaSE-1.8 (java-8-oracle). Click Finish. This resolves the error … Continue reading Error building Java Program in Eclipse Mars after changing Java version

How to resolve update-binfmts: warning: current package is oracle-java8, but binary format already installed by openjdk-7

I earlier had Oracle Java 7 installed on my Linux box. I upgraded to Oracle Java 8 as follows (below commands to be typed in a terminal window):$ sudo apt-get purge oracle-java7-installer <enter>$ sudo apt-get install oracle-java8-installer <enter> However, when Oracle Java 8 was downloaded and installed, I saw a message like this: update-binfmts: warning: … Continue reading How to resolve update-binfmts: warning: current package is oracle-java8, but binary format already installed by openjdk-7

GridLayout struggle when it has excess rows and how to overcome

In my Java code, I am using GridLayout (line shown in red) in code below: frame = new JFrame("Contacts Details"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); mainPanel = new JPanel(); buttonPanel = new JPanel(); mainPanel.setLayout(new GridLayout(9, 3)); buttonPanel.setLayout(new GridLayout(1, 3)); The result was this: Name [                        ] (Text Box for name) City [                        ] (Text Box for City) Cell [                        … Continue reading GridLayout struggle when it has excess rows and how to overcome

Where to place a text file for use with a Java project in Eclipse

I placed a text file myapp.txt in the folder ~/workspace/PayrollApp/src/org/username/payrollapp. However, it was not opening in the Java program. To make it work correctly, I had to do use the following path in the Java program when opening the file: src/org/username/payrollapp/pay.txt Code as follows: try { FileReader fr = new FileReader("src/org/username/payrollapp/pay.txt"); BufferedReader br = new … Continue reading Where to place a text file for use with a Java project in Eclipse