Java source, compiled will generate a. class text

I believe you have learned that Java has cross-platform features, you can "compile, run Everywhere", the program written under Windows, without any modification can be run under Linux, this is C and C + + difficult to do.


So how does cross-platform happen? This is about Java virtual machines (Javavirtualmachine, referred to as JVMs).


The JVM is also a software, and different platforms have different versions. We write the Java source code, compiled will generate a. class text, called bytecode file. The Java Virtual machine is responsible for translating bytecode files into the machine code under a specific platform and then running. That is, as long as the corresponding JVM is installed on different platforms, you can run bytecode files and run the Java programs that we write.


And in this process, we write the Java program did not make any changes, just through the JVM this "middle layer", can be run on different platforms, really realize the "compile, run everywhere" purpose.


Often on the internet to see a variety of titles as "Java Programmer", "PHP programmer", "c/E + + programmer" recruitment posts, but I feel this way of recruitment, it is difficult to find good talent. Language is just a tool, for a smart programmer, the use of what is not the main tool for his original work needs to decide, and does not represent all his skills.


In addition, a software product often involves many aspects of knowledge, such as networks, databases, Cache, compiling environment tools. If the necessary basic knowledge is insufficient, it is difficult to complete a part of a product independently.


On the other hand, a person's intelligence, curiosity about new knowledge, ego-driven awareness, the determination to find the best solution to the problem, is the key to his ability to become a good programmer. For instance, when I was a jpushcto, one of my colleagues was originally server-oriented in C language for development, and has no experience in iOS development, but he showed an interest in iOS development, and in the server-side development, demonstrated good learning ability, and then I transferred him to the iOS group, Responsible for IOSSDK and APNs related work, the results only took a few weeks, iossdk stability significantly increased, solve a number of fatal problems.


The reason why Java as the title, one is now the main Java language work is very much, and the other in the school to learn Java mainly people are more and more. But I have found that many of the basics of learning Java, a high-level language from school, are relatively weak. High-level language masks too much detail and improves productivity, but in the learning phase it is not conducive to the accumulation of basic knowledge.


The software industry is an industry that attaches great importance to the value of people, the value is reflected in the effective promotion of product progress, and language is only the tool to achieve this value.