Programming Articles - Page 2564 of 3363

We will face two cases while calling the parent constructor method in child class.Case1We can't run directly the parent class constructor in child class if the child class defines a constructor. In order to run a parent constructor, a call to parent::__construct() within the child constructor is required.Example Live DemoOutput: I am in Tutorials Point I am not in Tutorials PointExplanationIn the above example, we have used parent::__construct() to call the parent class constructor.Case2If the child does not define a constructor then it may be inherited from the parent class just like a normal class method(if it was not declared as ... Read More

The NumberFormatException is a class that represents an unchecked exception thrown by parseXXX() methods when they are unable to format (convert) a string into a number. Here, the parseXXX() is a group of Java built-in methods that are used to convert string representations of numbers into their corresponding primitive data types. Causes for NumberFormatException in Java The NumberFormatException extends IllegalArgumentException class of java.lang package. It can be thrown by many methods/constructors of the classes. Following are some of them: int parseInt(String s): It throws NumberFormatException if ... Read More

Java ArithmeticException The ArithmeticException of java.lang package is an unchecked exception in Java. It is raised when an attempt is made to use a wrong mathematical expression in the Java program. An example of ArithmeticExeption is division by 0. If you divide two numbers and the number in the denominator is zero. The Java Virtual Machine will throw ArithmeticException. Example: Throwing ArithmeticException In the following Java program, we try a mathematical operation where we divide a number by 0. public class ArithmeticExceptionTest { public static void main(String[] args) { int a ... Read More

The protected and default access modifiers determine how a member of a class or method can be accessed. The modifiers are attached to the members at the time of declaration. Since Java follows the object-oriented programming paradigm, these access modifiers are used in encapsulation, polymorphism, and inheritance to control the behavior of class members. We will try to understand the difference between protected and default access modifiers in Java through this article. Protected Access Modifier The protected access modifier is mostly used in the case of inheritance to control the access of parent class members and corresponding child class members. ... Read More

The OutOfMemoryError is thrown by JVM, when JVM does not have enough available memory, to allocate. OutOfMemoryError falls into the Error category in Exception class hierarchy.To generate OutOfMemoryErrorWe will allocate a large chunk of memory, which will exhaust heap memory storage.We will keep on allocating the memory and point will reach, when JVM will not have enough memory to allocate, then OutOfMemoryError will be thrown.Once we will catch the OutOfMemory error, we can log the error.ExampleLive Demopublic class OutOfMemoryErrorDemo {    public static void main(String[] args) throws Exception {       int dummyArraySize = 15;       System.out.println("Max JVM memory: " + Runtime.getRuntime().maxMemory()); ... Read More

No, we can not place any code after throw statement, it leads to compile time error. The compiler will show this error as unreachable statement. In Java, the throw statement immediately terminates the current flow of execution, therefore, the code immediate to a throw statement will not be executed. The control is then transferred to the next catch block or the caller method. The throw Keyword in Java The throw keyword is used to throw an exception manually. Whenever it is required to stop the execution of the functionality based on the user-defined logical error condition, we will use this ... Read More

In PHP, we utilize session_start() an inbuilt function to start the session .But the problem we face in a PHP script is if we execute it more than once it throws an error. So here we will learn how to check the session started or not without calling session_start() function twice.There are two ways to follow to resolve this problem.For below PHP 5.4.0 version.ExampleExplanationIf the session not started this code above will always start the session in the PHP script.In the second method, we can utilize the function session_status(), which returns the status of the present session. This function can ... Read More

An anonymous inner class is an inner class which is declared without any class name at all. In other words, a nameless inner class is called an anonymous inner class. Since it does not have a name, it cannot have a constructor because we know that a constructor name is the same as the class name.We can define an anonymous inner class and create its object using the new operator at the same time in one step.Syntaxnew(argument-list){    // Anonymous class body }Types of Anonymous Inner Class in JavaAnonymous inner class that extends a classAnonymous inner class that implements an interfaceAnonymous inner ... Read More

Hiding an e-mail addressThe following steps are to be followed to hide our e-mail from unauthorized users. In every email address '@' symbol is common so try to remove it from the email address using split() method. In the following example after splitting the email(batman@gmail.com) we get the result as batman, gmail.com.Divide the result in to 2 parts(split1 and split2). Using substring() method remove some of string from split1 and join resulted part with split2 using '...@'. Return the joined part as the final output. In our example the resulted output is "bat...@gmail.com".ExampleLive Demo newEmail = function (email) { ... Read More

The import statement is used to bring certain classes and interfaces from other packages into our Java program, so we can access them without using their fully qualified names. We can use the short name instead. Java also supports static import statements, which were introduced in Java 5. It helps in accessing static members such as methods and constants. In this article, we are going to learn the difference between import and static import statements in Java. The import Statement in Java To access a class or method from another package, we need to either use the fully qualified ... Read More