The important feature of Java that the computer programs written in Javsky language, should work as on any supported platform of hardware resources/operating systems. It is necessary be able write the program once, collect it once and control it somewhere.



The such has been reached, collecting the Javsky language code not to the machine code, and to the Javsky code of byte – the instruction similar to the machine code but which intended to be interpreted by the real computer (VM), written definitely for hardware of the master. End users usually use JRE, installed on their own computer or in a Web-browser.

The standardised libraries provide patrimonial path of reception of access to the master of certain features, such as a drawing. In some versions JVM the byte code can be collected to the native code, or before, or in program execution time that leads to faster performance.

The main benefit of usage of a code of byte this maintenance in a front rack. However, upper from interpretation means, that interpreted programs which almost always control more slowly than the programs collected to native executables, have brought to Java reputation of bad job. This interval has been narrowed by many optimisation techniques entered in fresher performance JVM.

One such engineering known as (timely compilation) the COIN In FIVE CENTS, translates the Javsky code of byte to the code of the native for the first time when the code is fulfilled. It leads to the program which starts performance faster, than the pure interpreted code can, at the expense of representation of casual compilation above in execution time. More difficult VMs also use dynamic recompilation in which VM parses behaviour of the streaming program and selectively repeatedly collects and optimises program parts. Dynamic recompilation can reach optimisation, above static compilation because the dynamic compiler can base optimisation on knowledge of environment in execution time and a set of the loaded classes, and can identify hotspots - program parts, often internal closed loops which occupy the majority of execution time. COIN compilation In FIVE CENTS and dynamic recompilation allow Javsky programs to come nearer to speed of the native code, not losing mobility.

Other engineering usually known as static compilation, or in good time (AOT) compilation, should collect directly in the native code as more traditional compiler. Static Javsky compilers translate the Javsky source or a byte code to the native code of the object. They reach good job in comparison with interpretation, at the expense of mobility; production of these compilers can be controlled on the unique architecture.

Job of Java has improved essentially, since early versions, and job of compilers of the COIN In FIVE CENTS concerning native code compilers also substantially. Job of compilers not without fail specifies compiled code job; only cautious testing can show true problems of job in any system.

One of unique advantages of concept of the engine in execution time - that errors (exception) should not ' divide ' system. Besides, in machine environment in execution time, such as Java, there are tools which are peculiar to the engine in execution time and each time when the interest exception occurs, they do a data recording of debugging which existed in memory when the exception has been thrown. These Automated Subsidiary tools of the Exception give the information ' original causes ' for exceptions in Javsky programs which run in production, testing or development environment.