How to specify filepath in java?
If you know the name of the file, of course it’s simply If you don’t know the name, you can use the File object’s list() method to get a list of files in the current directory, and then pick the one you want.
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Java Swing revalidate() vs repaint()
You need to call repaint() and revalidate(). The former tells Swing that an area of the window is dirty (which is necessary to erase the image of the old children removed by removeAll()); the latter tells the layout manager to recalculate the layout (which is necessary when adding components). This should cause children of the panel to repaint, but may not … Read more
Multidimensional Arrays lengths in Java
This will give you the length of the array at index i It’s important to note that unlike C or C++, the length of the elements of a two-dimensional array in Java need not be equal. For example, when pathList is instantiated equal to new int[6][], it can hold 6 int [] instances, each of which can be a different length. … Read more
Wrong project is being run in Eclipse
Trying to guess your problem: When you press the Run as button (White arrow in green circle), Eclipse doesn’t run the program you’re editing. Instead, it runs again the last program you executed. That’s the reason why you see the output of another project: You’re telling Eclipse to repeat its execution. So, to run your new app, … Read more
What is inverse function to XOR?
The inverse is XOR! If you have: You can get a or b back if you have the other value available: For example if a = 5, b = 3 (and thus c = 6 as you mentioned) you get:
Java “lambda expressions not supported at this language level”
In IntelliJ IDEA: In File Menu → Project Structure → Project, change Project Language Level to 8.0 – Lambdas, type annotations etc. For Android 3.0+ Go File → Project Structure → Module → app and In Properties Tab set Source Compatibility and Target Compatibility to 1.8 (Java 8) Screenshot:
String index out of bounds exception java
You are calling str.substring(i, j-i) which means substring(beginIndex, endIndex), not substring(beginIndex, lengthOfNewString). One of assumption of this method is that endIndex is greater or equal beginIndex, if not length of new index will be negative and its value will be thrown in StringIndexOutOfBoundsException. Maybe you should change your method do something like str.substring(i, j)? Also if size is length of your str then should probably be
intellij idea – Error: java: invalid source release 1.9
Select the project, then File > ProjectStructure > ProjectSettings > Modules -> sources You probably have the Language Level set at 9: Just change it to 8 (or whatever you need) and you’re set to go. Also, check the same Language Level settings mentioned above, under Project Settings > Project
Iterative Fibonacci code in Java?
In fibonacci sequence each item is the sum of the previous two. So, you wrote a recursive algorithm. So, Now you already know fibonacci(1)==1 and fibonacci(0) == 0. So, you can subsequently calculate the other values. Now, And from fibonacci sequence 0,1,1,2,3,5,8,13,21…. we can see that for 5th element the fibonacci sequence returns 5. like … Read more
The import org.junit cannot be resolved
You need to add junit library to the classpath of your project. There are several choices to achieve it depending on your development setup. Command line: In the case of command line invocations, you will have to add junit.jar to the classpath of your application with java -cp /path/to/junit.jar. Take a look at the answers here. Using eclipse: Eclipse distributions are … Read more