1, Java programs that run in a Web page called applet. To use the applet, requires a Java-enabled Web browser executes bytecode .
2, src.zip jdk installation files in the directory contains all public library source code. To get more of the source code (for example: compilers, virtual machines, methods, and local private helper classes), please visit the website: http: //jdk8.java.net.
3, does not apply to floating-point values can not be accepted financial calculation rounding error in. For example, the command System.out.println (2.0-1.1) will print .8999999999999999, rather than people think 0.9. The main reason is the rounding error value of the binary floating-point number system representation, in a binary system can not accurately represent the fraction 1/10. It's like not accurately represent the decimal fraction 1 / 3- kind.
4,