OpenJDK Runtime Environment (build 11.0.11+9-Ubuntu-0ubuntu2) It should output the following: openjdk version '11.0.11' We can check if OpenJDK JRE was properly installed by running: java -version To install the OpenJDK JRE, we run: sudo apt install default-jre (Alternatively, you may opt to use a specific Java version, using for example the openjdk-11-jre package as updates are released for that version of the Java Virtual Machine, that packages will be updated, allowing you to stick to the latest and greatest update of one specific version of the Java language.)

The default-jre is an excellent choice for most situations, thanks to the outstanding track of backwards compatibility of the Java Virtual Machine.

Ubuntu offers the default-jre package, which is regularly updated to ship the latest version of the current OpenJDK JRE in Long Term Support (LTS). Moreover, the non LTS versions of Java are bringing a steady stream of innovation into the language, and also see some adoption. Nowadays, Java 11 is the current Long Term Support (LTS) version, but Java 8 is still widely used. With new versions of Java released every 6 months, there are multiple versions available for use. The best way is to use a nested class, see example below:Ĭode listing 3.12: Multiple returned variables.Previous step Next step 2. This special object is 'bound' to this method and used only for returning values, so do not use a public class. Create that object inside the method, assign the values and return the reference to this object. There is a better approach, define a special return object with the needed return values.

However, this gives a problem if you want to mix primitive data types and object references as the output values from the method. You can also create an Object array inside the method, assign the return values and return the array to the caller. You can pass in an object reference to the method, and let the method modify the object properties so the modified values can be considered as an output value from the method. However, a method can return only one value so what if you want to return more than one value from a method? If the method does not return a value we use the void Java keyword. otherPoints ) Ī method may return a value (which can be a primitive type or an object reference). public void drawPolygon ( Point p1, Point p2, Point p3, Point. A polygon needs at least three points.

Java 11 install