A few things about the use of MYECLIPSE,JDK

"1" myeclipse How to modify JDK compilation version information

First open myeclipse--"windows--" preference (that is, the window-"preferences", you can enter the JDK in the search box, find;

Then click on JDK Compiler (compiler)--Choose your own JDK version or change according to the project requirements, of course, the version is not higher than the installed JDK,

"2"in Java. class files and. java Files

. java files are source files written in the Java language and compiled into corresponding *.class files

*.class files have a feature that compiles everywhere (that is, the Windows-generated class can run on Linux systems)
Note:
This *.class is not an executable file similar to *.exe
Can only be performed by a Java virtual machine

"3" buy the book to give information, only provide. Java code, you can create a new file copy code, you can directly copy the. java files under the project.

"4" The small exclamation point inside Java is a warning is not an error, many times because the variable declaration is not used, does not affect the compilation results.

A few things about the use of MYECLIPSE,JDK