What is the difference between a constructor and a method?
A constructor is a member function of a class that is used to create objects of that class. It has the same name as the class itself, has no return type, and is invoked using the new operator.
A method is an ordinary member function of a class. It has its own name, a return type (which may be void), and is invoked using the dot operator.
What will happen to the Exception object after exception handling?
Exception object will be garbage collected.
Difference between static and dynamic class loading.
Static class loading: The process of loading a class using new operator is called static class loading. Dynamic class loading: The process of loading a class at runtime is called dynamic class loading.
Dynamic class loading can be done by using Class.forName(….).newInstance().
Explain the Common use of EJB
The EJBs can be used to incorporate business logic in a web-centric application.
The EJBs can be used to integrate business processes in Business-to-business (B2B) e-commerce applications.In Enterprise Application Integration applications, EJBs can be used to house processing and mapping between different applications.
What is JSP?
JSP is a technology that returns dynamic content to the Web client using HTML, XML and JAVA elements. JSP page looks like a HTML page but is a servlet. It contains Presentation logic and business logic of a web application.
What is the purpose of apache tomcat?
Apache server is a standalone server that is used to test servlets and create JSP pages. It is free and open source that is integrated in the Apache web server. It is fast, reliable server to configure the applications but it is hard to install. It is a servlet container that includes tools to configure and manage the server to run the applications. It can also be configured by editing XML configuration files.
Where pragma is used?
Pragma is used inside the servlets in the header with a certain value. The value is of no-cache that tells that a servlets is acting as a proxy and it has to forward request. Pragma directives allow the compiler to use machine and operating system features while keeping the overall functionality with the Java language. These are different for different compilers.
Briefly explain daemon thread.
Daemon thread is a low priority thread which runs in the background performs garbage collection operation for the java runtime system.
What is a native method?
A native method is a method that is implemented in a language other than Java.
Explain different way of using thread?
A Java thread could be implemented by using Runnable interface or by extending the Thread class. The Runnable is more advantageous, when you are going for multiple inheritance.
What are the two major components of JDBC?
One implementation interface for database manufacturers, the other implementation interface for application and applet writers.
What kind of thread is the Garbage collector thread?
It is a daemon thread.
What are the different ways to handle exceptions?
There are two ways to handle exceptions,
1. By wrapping the desired code in a try block followed by a catch block to catch the exceptions. and
2. List the desired exceptions in the throws clause of the method and let the caller of the method handle those exceptions.
How many objects are created in the following piece of code?
MyClass c1, c2, c3;
c1 = new MyClass ();
c3 = new MyClass ();
Answer: Only 2 objects are created, c1 and c3. The reference c2 is only declared and not initialized.
What is UNICODE?
Unicode is used for internal representation of characters and strings and it uses 16 bits to represent each other.
Tags:
A constructor is a member function of a class that is used to create objects of that class. It has the same name as the class itself, has no return type, and is invoked using the new operator.
A method is an ordinary member function of a class. It has its own name, a return type (which may be void), and is invoked using the dot operator.
What will happen to the Exception object after exception handling?
Exception object will be garbage collected.
Difference between static and dynamic class loading.
Static class loading: The process of loading a class using new operator is called static class loading. Dynamic class loading: The process of loading a class at runtime is called dynamic class loading.
Dynamic class loading can be done by using Class.forName(….).newInstance().
Explain the Common use of EJB
The EJBs can be used to incorporate business logic in a web-centric application.
The EJBs can be used to integrate business processes in Business-to-business (B2B) e-commerce applications.In Enterprise Application Integration applications, EJBs can be used to house processing and mapping between different applications.
What is JSP?
JSP is a technology that returns dynamic content to the Web client using HTML, XML and JAVA elements. JSP page looks like a HTML page but is a servlet. It contains Presentation logic and business logic of a web application.
What is the purpose of apache tomcat?
Apache server is a standalone server that is used to test servlets and create JSP pages. It is free and open source that is integrated in the Apache web server. It is fast, reliable server to configure the applications but it is hard to install. It is a servlet container that includes tools to configure and manage the server to run the applications. It can also be configured by editing XML configuration files.
Where pragma is used?
Pragma is used inside the servlets in the header with a certain value. The value is of no-cache that tells that a servlets is acting as a proxy and it has to forward request. Pragma directives allow the compiler to use machine and operating system features while keeping the overall functionality with the Java language. These are different for different compilers.
Briefly explain daemon thread.
Daemon thread is a low priority thread which runs in the background performs garbage collection operation for the java runtime system.
What is a native method?
A native method is a method that is implemented in a language other than Java.
Explain different way of using thread?
A Java thread could be implemented by using Runnable interface or by extending the Thread class. The Runnable is more advantageous, when you are going for multiple inheritance.
What are the two major components of JDBC?
One implementation interface for database manufacturers, the other implementation interface for application and applet writers.
What kind of thread is the Garbage collector thread?
It is a daemon thread.
What are the different ways to handle exceptions?
There are two ways to handle exceptions,
1. By wrapping the desired code in a try block followed by a catch block to catch the exceptions. and
2. List the desired exceptions in the throws clause of the method and let the caller of the method handle those exceptions.
How many objects are created in the following piece of code?
MyClass c1, c2, c3;
c1 = new MyClass ();
c3 = new MyClass ();
Answer: Only 2 objects are created, c1 and c3. The reference c2 is only declared and not initialized.
What is UNICODE?
Unicode is used for internal representation of characters and strings and it uses 16 bits to represent each other.