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Java Articles
Page 122 of 450
How to convert string to array of integers in java?
You can convert a String to integer using the parseInt() method of the Integer class. To convert a string array to an integer array, convert each element of it to integer and populate the integer array with them.Exampleimport java.util.Arrays; public class StringToIntegerArray { public static void main(String args[]) { String [] str = {"123", "345", "437", "894"}; int size = str.length; int [] arr = new int [size]; for(int i=0; i
Read MoreWhat is the difference between class variables and instance variables in Java?
Following are the notable differences between Class (static) and instance variables. Instance variables Static (class) variables Instance variables are declared in a class, but outside a method, constructor or any block. Class variables also known as static variables are declared with the static keyword in a class, but outside a method, constructor or a block. Instance variables are created when an object is created with the use of the keyword 'new' and destroyed when the object is destroyed. Static variables are created when the program starts and destroyed when the program stops. ...
Read MoreHow to pass Arrays to Methods in Java?
You can pass arrays to a method just like normal variables. When we pass an array to a method as an argument, actually the address of the array in the memory is passed (reference). Therefore, any changes to this array in the method will affect the array.Suppose we have two methods min() and max() which accepts an array and these methods calculates the minimum and maximum values of the given array respectively:Exampleimport java.util.Scanner; public class ArraysToMethod { public int max(int [] array) { int max = 0; for(int i=0; imax) { ...
Read MoreHow to find a unique character in a string using java?
In this article, we will learn how to find a unique character in a string in Java. A unique character is a character that occurs only once in the string, while all others can occur multiple times. We can solve this problem using the following ways: Using Brute Force method. Using HashMap. Using brute force method To find a unique character in a given string, we will use a brute force approach. In the brute force approach, we will use two loops to compare each character to the rest of the string. Let's look at the steps: ...
Read MoreHow to check that a string is parse-able to a double in java?
Let's learn how to check if a string is parseable to a double in Java. We have multiple ways to do this. Some of them are: Using Double.parseDouble() Using Double.valueOf() Using the constructor of the Double class Using Double.parseDouble() The parseDouble() method of the java.lang.Double class accepts a String value, parses it, and returns the double value of the given String. If you pass a null value to this method, it throws a NullPointerException and if this method is not able to parse the given string ...
Read MoreWhat is ARM in Java?
Automatic resource management(ARM) or try-with-resources is a new exception handling mechanism that we are going to discuss in this article. What is a resource? A resource is an object which implements AutoClosable interface. Whenever you use a resource in your program, it is recommended to close it after use. For example, if you open a file using FileInputStream, it is recommended to close the stream after usage. This is done to free up the system resources. In Java, we can use the close() method to close the resources. But if you forget to close the resource, it will lead ...
Read MoreHow to insert a string in beginning of another string in java?
Let's learn how to add a string at the beginning of another string in Java. We can do this in the following ways: Using the toCharArray(). Using the String concatenation operator. Using the StringBuilder class. Using the StringBuffer class. Using the toCharArray() toCharArray() method of the String class that helps us to convert a string into a character array. We will use this method to insert a string at the beginning of another string. Following are the steps to do so: Get both strings, suppose we have a string str1 and the string to be added at ...
Read MoreHow to delete a string inside a file(.txt) in java?
In this article, we will learn how to delete a string inside a file (.txt) in Java. The following are the ways to do so: Using FileOutputStream and replaceAll() method. Using replace() method. Using FileOutputStream The FileOutputStream is a class in the java.io package. It is mainly used for writing data to a file. It creates a file output stream to write data to the specified file. To delete a string inside a file using the FileOutputStream class, follow the steps below: Create a file ...
Read MoreJava program to delete all the files in a directory recursively (only files)
To delete all the files in a directory recursively (only files), we can use the class Files, which is part of the java.nio.file package. The Files class helps in performing file operations such as creating, deleting, and copying files. Suppose we have a directory named test with the following structure: file1.txt file2.txt file3.txt subdir1 file4.txt file5.txt subdir2 ...
Read MoreRedirecting System.out.println() output to a file in Java
In Java, the System is a class that provides access to the resources called "System resources". It is a final class, which means it cannot be inherited by any other class. It is a part of the java.lang package. The System.out.println() method prints the data on the console. In this article, we will learn how to redirect the output of the System.out.println() method to a file. Following are few of the ways through we achieve this: Using System.setOut() with PrintStream Using FileOutputStream with PrintStream The filed named out of the System class represents a standard output Stream, an ...
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