If you want to move a file from one directory to anther in Java, you can use rename() method of File. The following is a simple code example for moving a file called “s1” to another directory. package com.programcreek; import java.io.File; public class MoveFileExample { public static void main(String[] args) { File … Read more
This is a method I write for merging two directories. The directory of second parameter will be moved to the first one, including files and directories. package com.programcreek; import java.io.File; public class MergeTwoDirectories { public static void main(String[] args){ String sourceDir1Path = "/home/programcreek/Desktop/d1"; String sourceDir2Path = "/home/programcreek/Desktop/d2"; File dir1 = new File(sourceDir1Path); … Read more
Read bytes from FileInputStream The following example shows how to read bytes from FileInputStream in Java. import java.io.File; import java.io.FileInputStream; public class fileInputStream { public static void main(String[] args) { byte[] data = new byte[1024]; //allocates memory for 1024 bytes //be careful about how to declare an array in Java int readBytes; try { File … Read more
Deleting files in Java is really simple. You can just use delete method of File. Here is a sample code: package file; import java.io.File; public class DeleteFile { public static void main(String[] args) { File file = new File("/home/programcreek/Desktop/s1"); if (file.delete()) { System.out.println(file.getName() + " is deleted!"); } else { System.out.println("File is … Read more
I often need to merge multiple files into one in Java. So I write a reusable method to do this job. It works very well for me to merge a set of txt files. The method accepts an array of File and the merged file path. After running the method, the set of files to … Read more
Before Java 7, if we need to copy a file we need to make a method or call the copyFile(File srcFile, File destFile) method of FileUtils inapache commons io package. In Java 7, file copy function is very simple. The following is a code example for showing how to use Files.copy() method: import java.io.IOException; import … Read more
Sorting a string LinkedList in Java is easy. You can sort the string LinkedList in ascending alphabetical order by using sort(List<T> list) . You can also sort the string LinkedList in descending alphabetical order by using sort(List<T> list, Comparator<? super T> c) . Here is the code: public static void main(String[] args) { LinkedList<String> stringList … Read more
If you know Java and want to quickly get a sense of how to use Python from the very beginning, the following summary can provide you a quick review of data types. You may also find the previous comparison of Java and Python useful. By comparing data types between Java and Python, you can get … Read more
Here is a method that can unzip/unjar .jar file and extract files inside to a destination directory. There are mainly 2 steps: 1) Create all directories inside of the jar file 2) Create all files inside of the jar file Since files in .jar is not in a certain order, we need to iterate twice … Read more
This is an example for showing how to use join(). Interview question: Use Java multi-threading to calculate the expression 1*2/(1+2). Solution: Use one thread to do addition, one thread to do multiplication, and a main thread to do the division. Since there is no need to communicate data between threads, so only need to consider … Read more
The large number of classes in the Java IO package is overwhelming and annoying. However, if we use Java, we still need to understand those classes. In fact, the classes in Java IO package is not very complex, but we need a good way to learn those. There are two important factors for understanding the … Read more
This code example shows how to parse HTML in Java by using jsoup. As there are many libraries for various purposes, there are a lot of html parser in Java. A lot of developers wonder which one is the best before they made a decision on an HTML parser. Jsoup is a very good start. … Read more
I posted this question on Stack Overflow today because the complete life cycle of a simple program is interesting. I will keep updating the post by using answers/comments to make it more complete and correct my mistake. I surely will up vote any answer/comment that makes sense. Please up vote or post answer/comment to help. … Read more
Given a garden with N slots. In each slot, there is a flower. Each of the N flowers will bloom one by one in N days. In each day, there will be exactly one flower blooming and it will stay blooming since then. Given an array of numbers from 1 to N. Each number in … Read more
Implement a MyCalendarTwo class to store your events. A new event can be added if adding the event will not cause a triple booking. Your class will have one method, book(int start, int end). Formally, this represents a booking on the half open interval [start, end), the range of real numbers x such that start