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What is Java programming?
Java:
Java is a programming language and computing platform launched by Sun Microsystems in 1995. There are many applications and websites that will not work unless you have Java installed and they are created every day. Java is fast, safe and reliable.
How does the java program work?
Compilation: In Java, programs are not compiled into executable files; they are compiled in bytecode (as discussed above), which JVM (Java Virtual Machine) executes at runtime. When the program is run, the byte code is converted using the just-in-time (JIT) compiler.
Java uses a garbage collector to manage memory in the object's life cycle. The programmer determines when the objects are created and Java Runtime is responsible for recovering the memory as soon as the objects are no longer in use.
Java Runtime Environment (JRE), which contains the parts of the Java SE platform required to run Java programs and is intended for end users. It allows you to declare a local variable without specifying its type.
The variable type is derived from the actual object type created. It's said to be the only real resource for developers in JDKOOP in Java.
The concepts of OOP in Java are the main ideas behind Java object oriented programming. They are an abstraction, encapsulation, inheritance and polymorphism.
Most people who are teaching math and math in the field of teaching. The idea of grouping data and methods that work on that data into one unit describes, for example, a class in Java. This concept is also often used to hide the internal representation or state of an external object.
In JDK, the components that formed a compiler (GC) implementation were distributed across various parts of the code base. It has been changed in Java 10. It is now a clean interface in JVM source code to allow alternative collectors to integrate quickly and easily. Source code isolation of different garbage collectors will be improved.
1)Abstraction:
Abstraction (from the Latin abs, which means distancing and trahere, which means drawing) is the process of removing or eliminating characteristics of something to reduce it to a set of essential characteristics.
2)Encapsulation:
Encapsulation in Java is a mechanism of wrapping the data (variables) and code acting on the data (methods) together as a single unit. Declare the variables of a class as private.
3) inheritance:
The inheritance can be defined as the process by which an object of one class acquires characteristics of the object of the other class. All objects of a similar type are grouped to form a class.
4) Polymorphism:
Generally, the ability to appear in many forms. In object-oriented programming, polymorphism refers to the ability of a programming language to process objects differently, depending on their type or class of data. More specifically, it is the ability to redefine methods for derived classes.
Javac in Java:
• Javac is the main Java compiler included in the Oracle Corporation Java Development Kit (JDK). The compiler accepts source code according to the Java language specification (JLS) and produces Java code according to the Java specification (JVMS).
• A Java compiler is a compiler for the java programming language. The most common way to generate a Java compiler is Java class files that contain Java platform neutral bytecode, but there are also compilers that provide native machine code optimized for a specific hardware / operating system combination.
• Garbage collection can at any time. Ideally, this will occur when a program is inactive. It is guaranteed to activate if there is enough free memory in the heap to allocate a new object; This may cause a program to stop momentarily. Explicit memory management is not possible in Java.
Data Exchange Class:
The purpose of this function is to improve startup space and extend the existing "Class-Data Sharing" (CDS) function to allow application classes to be placed in the shared file.
The shared data class, introduced in JDK 5, a set of classes is preprocessed into a shared file, which can be allocated in memory at run time to reduce startup time. You can also reduce the dynamic memory footprint when multiple JVMs share the same file.
Currently, CDS only allows the startup class loader to load archived classes. Application CDS allows the integrated system class loader, integrated platform class loader, and custom class loaders to load archived classes.
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