super() calls the parent constructor with no arguments. It can be used also with arguments. I.e. super(argument1) and it will call the constructor that accepts 1 parameter of the type of argument1 (if exists). Also it can be used to call methods from the parent. I.e. super.aMethod() More info and tutorial here
There are working combinations of OS, JDK and Eclipse bitness. In my case, I was using a 64-bit JDK with a 32-bit Eclipse on a 64-bit OS. After downgrading the JDK to 32-bit, Eclipse started working. Use one of the following combinations. 32-bit OS, 32-bit JDK, 32-bit Eclipse (32-bit only) 64-bit OS, 32-bit JDK, 32-bit … Read more
You can use Character.toString(char). Note that this method simply returns a call to String.valueOf(char), which also works. As others have noted, string concatenation works as a shortcut as well: But this compiles down to: which is less efficient because the StringBuilder is backed by a char[] (over-allocated by StringBuilder() to 16), only for that array to be defensively copied by the resulting String. String.valueOf(char) “gets in … Read more
There are working combinations of OS, JDK and Eclipse bitness. In my case, I was using a 64-bit JDK with a 32-bit Eclipse on a 64-bit OS. After downgrading the JDK to 32-bit, Eclipse started working. Use one of the following combinations. 32-bit OS, 32-bit JDK, 32-bit Eclipse (32-bit only) 64-bit OS, 32-bit JDK, 32-bit … Read more
Summary ArrayList with ArrayDeque are preferable in many more use-cases than LinkedList. If you’re not sure — just start with ArrayList. TLDR, in ArrayList accessing an element takes constant time [O(1)] and adding an element takes O(n) time [worst case]. In LinkedList adding an element takes O(n) time and accessing also takes O(n) time but LinkedList … Read more
java.exe is the command where it waits for application to complete untill it takes the next command. javaw.exe is the command which will not wait for the application to complete. you can go ahead with another commands.
Run the JVM with -XX:MaxHeapSize=512m (or any big number as you need) (or -Xmx512m for short)
Note that each of the code samples below may throw IOException. Try/catch/finally blocks have been omitted for brevity. See this tutorial for information about exception handling. Note that each of the code samples below will overwrite the file if it already exists Creating a text file: Creating a binary file: Java 7+ users can use the Files class to write to … Read more
I don’t think there is a general purpose tuple class in Java but a custom one might be as easy as the following: Of course, there are some important implications of how to design this class further regarding equality, immutability, etc., especially if you plan to use instances as keys for hashing.
Use setRoundingMode, set the RoundingMode explicitly to handle your issue with the half-even round, then use the format pattern for your required output. Example: gives the output: EDIT: The original answer does not address the accuracy of the double values. That is fine if you don’t care much whether it rounds up or down. But … Read more