Table of Contents
- 1 What are the different class loaders used by JVM?
- 2 What is class loader and types of class loader in Java?
- 3 How do class loaders work in Java?
- 4 What is custom class loader in Java?
- 5 What is JDBC class forName?
- 6 What is Socket class for?
- 7 When and how a Java class is loaded and initialized?
- 8 How is classloader works in Java?
- 9 What is classloader in Java?
What are the different class loaders used by JVM?
When the JVM is started, three class loaders are used:
- Bootstrap class loader.
- Extensions class loader.
- System class loader.
What is class loader and types of class loader in Java?
System ClassLoader: An Application ClassLoader is also known as a System ClassLoader. It loads the Application type classes found in the environment variable CLASSPATH, -classpath or -cp command line option. The Application ClassLoader is a child class of Extension ClassLoader.
What are the different ways to load a class in Java?
What are the different ways to load a class in Java?
- Reference the class name in code. The class will be loaded when JVM find the class available in the classpath.
- Using Class. forName(String), to load and initialize the class.
- ClassLoader. getSystemClassLoader().
- Overloaded Class.forName()
How do class loaders work in Java?
Java class loaders are used to load classes at runtime. ClassLoader in Java works on three principles: delegation, visibility, and uniqueness. Delegation principle forward request of class loading to parent class loader and only loads the class if the parent is not able to find or load the class.
What is custom class loader in Java?
java. lang. ClassLoader loads a class. Using ClassLoader, we can load classes from desired location like from another location etc. A custom ClassLoader is a sub class of ClassLoader which will override some methods of ClassLoader.
What is dynamic class loading in Java?
Dynamic Class Loading allows the loading of java code that is not known about before a program starts. The Java model loads classes as needed and need not know the name of all classes in a collection before any one of its classes can be loaded and run. You can create object at run time by dynamic class loading.
What is JDBC class forName?
Use the Class. forName() method to load the driver. The forName() method dynamically loads a Java class at runtime. When an application calls the forName() method, the JVM (Java Virtual Machine) attempts to find the compiled form (the bytecode) that implements the requested class.
What is Socket class for?
The Socket class is used to communicate client and server. Through this class, we can read and write message. The ServerSocket class is used at server-side. The accept() method of ServerSocket class blocks the console until the client is connected.
What is static class loading in Java?
In static class loading Classes are statically loaded with Java’s “new” operator. In this case, the retrieval of class definition and instantiation of the object is done at compile time.
When and how a Java class is loaded and initialized?
A class is initialized when a symbol in the class is first used. When a class is loaded it is not initialized. JVM will initialize superclass and fields in textual order, initialize static, final fields first, and give every field a default value before initialization.
How is classloader works in Java?
How Java ClassLoader Works? The java.util.HashMap ClassLoader is coming as null, which reflects Bootstrap ClassLoader. When we are trying to load HashMap, our System ClassLoader delegates it to the Extension ClassLoader. The same process is followed for the DNSNameService class.
What is class loading in Java?
Java class loader are used in loading classes at run time execution point. It is a part of java run time environment used in loading files and files systems into the program to be executed. With the presence of class loader, delegation of functions for other variables, constant and classes becomes easier.
What is classloader in Java?
ClassLoader in Java is a class which is used to load class files in Java. Java code is compiled into class file by javac compiler and JVM executes Java program, by executing byte codes written in class file.