Java Tutorial

by Dinesh Thakur Category: Java Evolution

The means that allows Java to solve both the security and the portability problems is that the output of a Java compiler is not executable code but it is the Bytecode. Bytecode is a highly optimized set of instructions designed to be executed by the Java run-time system, which is called the lava Virtual Machine (JVM). JVM is an interpreter for bytecode. The fact that a Java program is executed by JVM helps solve the major problems associated with downloading programs over the Internet. Translating a Java program into bytecode helps makes it much easier to run a program in a wide variety of environments. This is because only the JVM needs to be implemented for each platform.

 
by Dinesh Thakur Category: Java Evolution

The JRE is the smallest set of executables and files that constitute the standard java plot form.The Java Runtime Environment (JRE) provides the libraries, the Java Virtual Machine, and other components to run applets and applications written in the Java programming language. In addition, two key deployment technologies are part of the JRE:



 
by Dinesh Thakur Category: Java Evolution

Java Virtual Machine (JVM)

JVM is a set of computer software programs and data structures which implements a specific Virtual machine model.



 
by Dinesh Thakur Category: Java Evolution

(Open Database Connectivity) An APPLICATION PROGRAMMING INTERFACE published by Microsoft which, by loading the appropriate ODBC driver at run time, enables the same program code to have access to data from many different brands of database.



 
by Dinesh Thakur Category: Java Evolution

The JAR file (Java ARchive) is a way to compress multiple files in Java, as well as a ZIP. Usually the classes and other configuration files are stored.
As they grouped several classes in a single file, they are great for distributing libraries, such as database drivers, frameworks, systems modules, etc.



 
by Dinesh Thakur Category: Data Type

A variable in a program occupies some space in computer's memory where some value is stored. A value to be stored may be an integer, floating point number, a character or a string. However, now the question arises that how much memory is allocated to these values and what is the range of values that can be stored in it as different types of values don't occupy same space in memory. So to store these values, we require different data types depending on the needs of the application. The data type determines how much memory is allocated to store data and what operations can be performed on it. The Data type also defines the values that a variable can takes.



 
by Dinesh Thakur Category: Data Type

Vectors:- We know that Arrays are very useful when there is a need to use number of variables But There is a problem with Array they use only single data type or The Elements of array are always Same type For Avoiding this Problem Vectors are used.



 
by Dinesh Thakur Category: Data Type

The scope of a variable specifies the region of the source program where that variable is known, accessible and can be used. In Java, the declared variable has a definite scope. When a variable is defined within a class, its scope determines whether it can be used only within the defined class or outside of the class also.

 
by Dinesh Thakur Category: Data Type

Operator is a symbol that represents some operation that can be performed on data. The operators are applied to operands (onto which processing is desired). These operands can be literals, variables etc. The operators supported by Java are as follows:

 
by Dinesh Thakur Category: Data Type

Automatic memory management, also known as automatic garbage collection, is the practice of allowing the language implementation to keep track of used and unused memory, freeing the programmer from this burden.

 

Page 6 of 80



About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.