Java introduction смотреть онлайн

The five primary goals of the Java language are these:
One design goal of Java is portability, the programs written in the Java platform must run similarly on any combination of hardware and operating system with adequate runtime support. This is achieved by compiling the Java language code to an intermediate representation called Java bytecode, instead of architecture-specific machine code.
Java bytecode instructions are analogous to machine code, but they are intended to be executed by a virtual machine (VM) written specifically for the host hardware. End users commonly use a Java Runtime Environment (JRE) installed on their own machine for standalone Java applications, or in a web browser for Java applets.
Platform independent language, designed to have as few implementation dependencies as possible.
Concurrent computing (where multiple computations can happen at the same time.)
Class-based ( is a style of object-oriented programming (OOP) in which inheritance is achieved by defining classes of objects, as opposed to the objects themselves)
Write once, run anywhere meaning that compiled Java code can run on all platforms that support Java without the need for recompilation.
Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of computer architecture.
As of 2016, Java is one of the most popular programming languages in use, particularly for client-server web applications, with a reported 9 million developers.
Java requires that each variable be initialized to improve security. Some older languages such as C, allow variables to go uninitialized, which can cause random failures with mysterious bugs.
Java requires that each method that declares a return type, always return a value. This also prevents bugs.
Java API is most useful without having to develop much code. Java comes with a large set of classes and methods, the Java API that can be used without having to develop as much code "from scratch".
Code compiles on one Java platform can be run on other platforms that support Java without modification of either the source-code or the byte-code. For example, this means that a person can make a Java program for a Windows computer and have it run a Linux or a Mac computer.
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The Java platform is used to develop and run Java programs. The platform includes the execution engine (called a Java Virtual Machine) that allows Java programs to do the same thing on different computer systems.
This capability of being able to develop software on one platform and running it on other platforms is called "cross-platform capability"