Java String import
I have one doubt. When we use ArrayList or HashMap in Java, we have to import java.util.ArrayList or java.util.HashMap. But when we use String, it doesn’t require the import statement. Can anyone clarify, why?
Java
What’s the difference between JPA and Hibernate?
I understand that JPA 2 is a specification and Hibernate is a tool for ORM. Also, I understand that Hibernate has more features than JPA 2. But from a practical point of view, what really is the difference? I have experience using iBatis and now I’m trying to learn either Hibernate or JPA2. I picked … Read more
Invalid initial heap size. Could not create the Java virtual machine
got the correct parameters(JAVA_OPTS) from here. I’ve set them in setenv.bat.
JavaFX and OpenJDK
JavaFX is part of OpenJDK The JavaFX project itself is open source and is part of the OpenJDK project. However, the OpenJDK project includes many projects, including incubating projects and other projects, such as OpenJFX, whose source and implementation are not shipped as part of some JDK/JRE distributions (e.g. Oracle JDK 11+ implementations and many … Read more
How to use a Do-while loop that continuously prompts a user?
(I have a homework question that I’ve been stuck on that concerns “do-while loops” in Java. ) It is asking me to have a do-while loop that continues to prompt a user to enter a “number less than 100”, up until the entered number is actually less than 100. (It will run three tests:) Ex: … Read more
How do I exit a while loop in Java?
Use break: However, if your code looks exactly like you have specified you can use a normal while loop and change the condition to obj != null:
Android Emulator: Unfortunately App has stopped
change apptheme to Theme.AppCompat in your manifest.xml This worked initially but later on after making the theme back to AppTheme worked too
Create a two dimensional string array anArray[2][2]
Looks like this is what you want Here I’ll explain the code: This declares the size of your new 2D array. In Java (and most programming languages), your first value starts at 0, so the size of this array is actually 2 rows by 2 columns Here you are using the type String[][] to create a new … Read more
Resource leak: ‘in’ is never closed
Why does Eclipse give me the warming “Resource leak: ‘in’ is never closed” in the following code?
Convert double to Int, rounded down
If you explicitly cast double to int, the decimal part will be truncated. For example: Moreover, you may also use Math.floor() method to round values in case you want double value in return.