Java中的Path和ClassPath有什么区别？

Question

Why do we need Path and ClassPath? When using IDE's like eclipse we still need to add path ?

Answer 1

path 是开发人员和操作系统之间的中介，用于通知二进制文件路径，而 Classpath 是开发人员和编译器之间的中介，用于通知我们源代码中使用的库文件路径

Answer 2

We don't need to set PATH and CLASSPATH to compile and run java program while using IDE like Eclipse .
These environment variables are required to compile and run java program using CMD .

Example-: Here is the screen shot of console to understand PATH and CLASSPATH quickly

Explanation-:

Compiling the program- I have java program file Demo.java stored at location D:\\Programs\\Classes . Now I pointed location to D:\\Programs\\Classes in CMD and executed javac Demo.java command. System will understand javac with the help of PATH variable. Java program Demo.java is complied successfully because PATH is set correctly to %JAVA_HOME%\\bin .

Running the program (class file)- Since class file has been generated at the same location D:\\Programs\\Classes , so we can run this class file by typing command java Demo as displayed in second line in the screenshot. Now system will find the class file with the help of CLASSPATH since my CLASSPATH variable has D:\\Programs\\Classes path.

It's not required to point class file location in CMD to run it. System will understand java command with the help of PATH variable and find that class using CLASSPATH variable to run it.

Answer 3

The path points to the location of the jre ie the java binary files such as the jvm and necessary libraries. The classpath points to the classes you developed so that the jvm can find them and load them when you run your product.

So essentially you need the path to find java so it can then find your classes and run them from the classpath

Answer 4

let us clear the difference in points:

PATH

a) An environment variable which is used by the operating system to find the executables.

b) PATH is nothing but setting up an environment for operating system. Operating System will look in this PATH for executables.

c) Refers to the system

CLASSPATH

a) An environment variable which is used by the Java compiler to find the path, of classes ie in J2EE we give the path of jar files.

b) Classpath is nothing but setting up the environment for Java. Java will use to find compiled classes.

c) Refers to the Developing Enviornment.

Answer 5

The main difference between PATH and CLASSPATH is that PATH is an environment variable which is used to locate JDK binaries like "java" or "javac" command used to run java program and compile java source file. On the other hand, CLASSPATH, an environment variable is used by System or Application ClassLoader to locate and load compile Java bytecodes stored in the .class file.

For more info: http://www.java67.com/2012/08/what-is-path-and-classpath-in-java-difference.html

Answer 6

path : it is location of bin files(binary executable files) example- java.exe,javac.exe

classPath: it is location of your .class file(which is created after compile your java source file)

Answer 7

Path and Classpath both are operating system level environment variales. Path is used define where the system can find the executables(.exe) files and classpath is used to specify the location .class files.

Answer 8

PATH is the environment variable where we specify the locations of binaries.
Example: We add bin directory path of JDK or JRE, so that any binaries under the directory can be accessed directly without specifying absolute path.

CLASSPATH is the path for Java application where the classes you compiled will be available.

Answer 9

Difference between path and classpath

Difference between path and classpath in Java

path is set for use java tool in your java program like java, javac, javap. javac are used for compile the code. and classpath are used for use predefined class in your program for example use scanner class in your program for this you need to set classpath.

http://www.tutorial4us.com/java/difference-between-path-and-classpath