More than 3000 questions in repository. There are more than 900 unanswered questions. Click here and help us by providing the answer. Have a video suggestion. Click Correct / Improve and please let us know.
Ans. 1. when an OS wants to start running program it creates new process means a process is a program that is currently executing and every process has at least one thread running within it. 2). A thread is a path of code execution in the program, which has its own local variables, program counter(pointer to current execution being executed) and lifetime. 3. When the JavaVirtual Machine (JavaVM, or just VM) is started by the operating system, a new process is created. Within that process, many threads can be created. 4. Consider an example : when you open Microsoft word in your OS and you check your task manger then you can see this running program as a process. now when you write something in opened word document, then it performs more than one work at same time like it checks for the correct spelling, it formats the word you enter , so within that process ( word) , due to different path execution(thread) all different works are done at same time. 5. Within a process , every thread has independent path of execution but there may be situation where two threads can interfere with each other then concurrency and deadlock come is picture. 6. like two process can communicate ( ex:u open an word document and file explorer and on word document you drag and drop another another file from file explorer), same way two threads can also communicate with each other and communication with two threads is relatively low. 7. Every thread in java is created and controlled by unique object of java.lang.Thread class. 8. prior to jdk 1.5, there were lack in support of asynchronous programming in java, so in that case it was considered that thread makes the runtime environment asynchronous and allow different task to perform concurrently.
Help us improve. Please let us know the company, where you were asked this question :
Q418. What restrictions are placed on method overriding?
Ans. Overridden methods must have the same name, argument list, and return type. The overriding method may not limit the access of the method it overrides. The overriding method may not throw any exceptions that may not be thrown by the overridden method.
Help us improve. Please let us know the company, where you were asked this question :
Ans. When an exception is thrown within the body of a try statement, the catch clauses of the try statement are examined in the order in which they appear. The first catch clause that is capable of handling the exception is executed. The remaining catch clauses are ignored.
Help us improve. Please let us know the company, where you were asked this question :
Ans. RMI stands for Remote Method Invocation. Traditional approaches to executing code on other machines across a network have been confusing as well as tedious and error-prone to implement. The nicest way to think about this problem is that some object happens to live on another machine, and that you can send a message to the remote object and get a result as if the object lived on your local machine. This simplification is exactly what Java Remote Method Invocation (RMI) allows you to do.
Help us improve. Please let us know the company, where you were asked this question :
Ans. JMS Provides high-performance asynchronous messaging. It enables Java EE applications to communicate with non-Java systems on top of various transports.
Help us improve. Please let us know the company, where you were asked this question :
Ans. EJB Provides a mechanism that make easy for Java developers to use advanced features in their components, such as remote method invocation (RMI), object/ relational mapping (that is, saving Java objects to a relational database), and distributed transactions across multiple data sources.
Help us improve. Please let us know the company, where you were asked this question :
Ans. A static initialization block is a normal block of code enclosed in braces, { }, and preceded by the static keyword. Here is an example:
static {
// whatever code is needed for initialization goes here
}
A class can have any number of static initialization blocks, and they can appear anywhere in the class body. The runtime system guarantees that static initialization blocks are called in the order that they appear in the source code.
Help us improve. Please let us know the company, where you were asked this question :
Ans. Sometime we just need classes or class objects just to be used as part of a particular class or objects. Making them non nested won't make any difference as far as functionality is concerner but making them Nested provide a level of convenience and protection fro, being used anywhere else. Moreover it helps reducing the Code.
Help us improve. Please let us know the company, where you were asked this question :
Ans. Annotations, a form of metadata, provide data about a program that is not part of the program itself. Annotations have no direct effect on the operation of the code they annotate. Annotations have a number of uses, among them: • Information for the compiler — Annotations can be used by the compiler to detect errors or suppress warnings. • Compile-time and deployment-time processing — Software tools can process annotation information to generate code, XML files, and so forth. • Runtime processing — Some annotations are available to be examined at runtime.
Help us improve. Please let us know the company, where you were asked this question :
Q430. Difference between implicit and explicit type casting ?
Ans. An explicit conversion is where you use some syntax to tell the program to do a conversion whereas in case of implicit type casting you need not provide the data type.
Help us improve. Please let us know the company, where you were asked this question :
More than 3000 questions in repository.
Very frequently asked. Usually asked in this format or as difference with interfaces / concrete classes.
Discuss 
abstract class 
Asked in 6 Companies 
basic 
frequent
Try 3 Question(s) Test
Which of the following can be marked static ?
