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Articles by Maruthi Krishna
Page 22 of 50
Why static methods of parent class gets hidden in child class in java?
When we have two classes where, one extends another and if, these two classes have same method including parameters and return type (say, sample) the method in the sub class overrides the method in the super class.i.e. Since it is inheritance. If we instantiate the subclass a copy of superclass’s members is created in the subclass object and, thus both methods are available to the object of the subclass.But if you call the method (sample), the sample method of the subclass will be executed overriding the super class’s method.Exampleclass Super{ public static void sample(){ System.out.println("Method of ...
Read MoreHow to call a non-static method of an abstract class from a static method in java?
A method which does not have body is known as abstract method. It contains only method signature with a semi colon and, an abstract keyword before it.public abstract myMethod();To use an abstract method, you need to inherit it by extending its class and provide implementation to it.Abstract classA class which contains 0 or more abstract methods is known as abstract class. If it contains at least one abstract method, it must be declared abstract.Hence, if you want to prevent instantiation of a class directly, you can declare it abstract.Accessing non-static methods of an abstract classSince you cannot instantiate an abstract ...
Read MoreCan we make static reference to non-static fields in java?
A class in Java will have three kinds of variables namely, static (class), instance and, local.Local variables − These variables belong to and declared/defined within the methods/blocks/constructors. The scope of these variables lies within the method (or, block or, constructor) and will be destroyed after he execution of it.Instance variables − These variables belong to the instances (objects) of a class. These are declared within a class but outside methods. These are initialized when the class is instantiated. They can be accessed from any method, constructor or blocks of that particular class.You must access instance variables using an object. i.e. ...
Read MoreWhat is the syntax for passing Scanner object as a parameter in a method using java?
Until Java 1.5 to read data from the user programmers used to depend on the character stream classes and byte stream classes.From Java 1.5 Scanner class was introduced. This class accepts a File, InputStream, Path and, String objects, reads all the primitive data types and Strings (from the given source) token by token using regular expressions.By default, whitespace is considered as the delimiter (to break the data into tokens).To read various datatypes from the source using the nextXXX() methods provided by this class namely, nextInt(), nextShort(), nextFloat(), nextLong(), nextBigDecimal(), nextBigInteger(), nextLong(), nextShort(), nextDouble(), nextByte(), nextFloat(), next().Passing Scanner object as a ...
Read MoreHow to fix "Exception in thread main" in java?
An exception is an issue (run time error) occurred during the execution of a program. When an exception occurred the program gets terminated abruptly and, the code past the line that generated the exception never gets executed.Exampleimport java.util.Scanner; public class ExceptionExample { public static void main(String args[]) { Scanner sc = new Scanner(System.in); System.out.println("Enter first number: "); int a = sc.nextInt(); System.out.println("Enter second number: "); int b = sc.nextInt(); int c = a/b; System.out.println("The result is: "+c); ...
Read MoreCan we declare a static variable within a method in java?
A static filed/variable belongs to the class and it will be loaded into the memory along with the class. You can invoke them without creating an object. (using the class name as reference). There is only one copy of the static field available throughout the class i.e. the value of the static field will be same in all objects. You can define a static field using the static keyword.Examplepublic class Sample{ static int num = 50; public void demo(){ System.out.println("Value of num in the demo method "+ Sample.num); } public static void main(String ...
Read MoreHow and where does String literals in Java stored in the memory?
Strings are used to store a sequence of characters in Java, they are treated as objects. The String class of the java.lang package represents a String.You can create a String either by using the new keyword (like any other object) or, by assigning value to the literal (like any other primitive datatype).Examplepublic class StringDemo { public static void main(String args[]) { String stringObject = new String("Hello how are you"); System.out.println(stringObject); String stringLiteral = "Welcome to Tutorialspoint"; System.out.println(stringLiteral); } }OutputHello how are you Welcome to TutorialspointStorage of ...
Read MoreWhy should you be careful about String concatenation (+) operator in loops using Java?
Strings are used to store a sequence of characters in Java, they are treated as objects. The String class of the java.lang package represents a String.You can create a String either by using the new keyword (like any other object) or, by assigning value to the literal (like any other primitive datatype).Public class Sample{ Public static void main(String args[]){ String str1 = "Hello"; String str2 = "how are you"; } }Strings are immutable in Java i.e. once you create a String literal it cannot be modified.StorageSince all the String values we define ...
Read MoreIn how many ways we can concatenate Strings in Java?
Strings are used to store a sequence of characters in Java, they are treated as objects. The String class of the java.lang package represents a String.You can create a String either by using the new keyword (like any other object) or, by assigning value to the literal (like any other primitive datatype).String stringObject = new String("Hello how are you"); String stringLiteral = "Welcome to Tutorialspoint";Concatenating StringsYou can concatenate Strings in Java in the following ways −Using the "+" operator: Java Provides a concatenation operator using this, you can directly add two String literalsExampleimport java.util.Scanner; public class StringExample { public ...
Read MoreHow do we set the Java environment variable in cmd.exe?
When you install Java in your system first of all you need to set the environment variables which are path and class path.PATH− The path environment variable is used to specify the set of directories which contains executional programs.When you try to execute a program from command line, the operating system searches for the specified program in the current directly, if available, executes it.In case the programs are not available in the current directory, operating system verifies in the set of directories specified in the ‘PATH’ environment variable.You need to set path for compiler (javac.exe) and JVM(java.exe), which exists in ...
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