This question is not particularly related to Java and also asked on other programming interviews e. I have included this in my list of frequently asked questions from Java interviews because I have seen it more often than not. If I say that this is one of the most most frequently asked question to Java programmers, then it would not be wrong.
The "2" was originally intended to emphasize the major changes introduced in version 1. The naming convention has been changed several times over the Java version history.
Starting with J2SE 1. Java Platform, Enterprise Edition Java EE is a related specification that includes all the classes in Java SE, plus a number that are more useful to programs that run on servers as opposed to workstations. Java Platform, Micro Edition Java ME is a related specification intended to provide a certified collection of Java APIs for the development of software for small, resource-constrained devices such as cell phonesPDAs and set-top boxes.
General purpose packages[ edit ] java. This includes the root classes that form the class hierarchytypes tied to the language definition, basic exceptionsmath functions, threadingsecurity functions, as well as some information on the underlying native system.
This package contains 22 of 32 Error classes provided in JDK 6. The main classes and interfaces in java. Object — the class that is the root of every class hierarchy. Enum — the base class for enumeration classes as of J2SE 5.
Class — the class that is the root of the Java reflection system. Throwable — the class that is the base class of the exception class hierarchy. ErrorExceptionand RuntimeException — the base classes for each exception type.
Thread — the class that allows operations on threads. String — the class for strings and string literals. Comparable — the interface that allows generic comparison and ordering of objects as of J2SE 1. Iterable — the interface that allows generic iteration using the enhanced for loop as of J2SE 5.
ClassLoaderProcessRuntimeSecurityManagerand System — classes that provide "system operations" that manage the dynamic loading of classes, creation of external processeshost environment inquiries such as the time of day, and enforcement of security policies.
The basic exception classes thrown for language-level and other common exceptions. It is an important package, central enough to the language for the language designers to give it a name that starts with "java. This package was added in J2SE 1.
Java has an expressive system of references and allows for special behavior for garbage collection. A normal reference in Java is known as a "strong reference. Each type of reference is designed for a specific use.
A SoftReference can be used to implement a cache. An object that is not reachable by a strong reference that is, not strongly reachablebut is referenced by a soft reference is called "softly reachable.
This generally means that softly reachable objects are only garbage collected when free memory is low—but again, this is at the garbage collector's discretion.Java i About the Tutorial Java is a high-level programming language originally developed by Sun Microsystems and released in Java runs on a variety of .
Note that, if there were a field that is a pointer or reference to another object, then it might still be possible to mutate the object pointed to by such a pointer or reference within a const method, without violating const-correctness.
When Vert.x provides an event to a handler or calls the start or stop methods of a Verticle, the execution is associated with a ashio-midori.comy a context is an event-loop context and is tied to a specific event loop thread.
So executions for that context always occur on that exact same event loop thread. Jun 29, · Thread term can be used in two ways. An instance of class ashio-midori.com; A Thread of Execution; An Instance of Thread is an object like any other object in Java, and it contains variables and methods which lives and dies on the heap.
But a Thread of Execution is an individual process which has its stack ashio-midori.com if you don’t create any thread in your program, a thread will be running. Java Multithreaded Programming A er learning the contents of this chapter, the reader must be able to: ∑ understand the importance of concurrency ∑ understand multithreading in Java ∑ create user-deﬁ ned classes with thread capability ∑ write multithreaded server programs ∑ understand the concurrent issues with thread programming This chapter presents multithreading, which is one.
Oct 08, · Implementing the ashio-midori.comle interface.; Extending the ashio-midori.com class.; Java Thread Example – implementing Runnable interface.
To make a class runnable, we can implement ashio-midori.comle interface and provide implementation in public void run() method. To use this class as Thread, we need to create a Thread object by passing object of this runnable class .