问题
I have a problem involving setting up Java.
I have installed the JRE, added its path to PATH, and set JAVA_HOME and CLASSPATH. Now, java and javacpl work fine, but running javac generates a command-not-found error. Furthermore, javac.exe does not even seem to exist in the JRE's bin folder.
How do I run javac?
回答1:
The JRE is merely the Java Runtime Environment, which includes only the infrastructure needed to run Java programs that are already compiled.
To compile Java source code using javac, you need the Java Development Kit (JDK).
On Oracle's Java download page, choose the package labelled "JDK".
回答2:
In order to use javac in cmd , JDK must be installed in your system...
javac will not work if you are pointing "bin" folder inside JRE (C:\Program Files\Java**jre7**\bin)
Please check for javac.exe inside your bin folder(C:\Program Files\Java**jdk1.7.0_45**\bin)
javac.exe must be inside JDK(C:\Program Files\Java\jdk1.7.0_45\bin) not inside JRE (C:\Program Files (x86)\Java\jre7\bin) "JRE doesn't come with a compiler. It is simply a java runtime environment. What you need is the developmental kit." in order to use compiler javac
For javac path(Points to remember while setting system env variable)
path = C:\Program Files (x86)\Java\jre7\bin this is wrong
path = C:\Program Files\Java\jdk1.7.0_45\bin this is correct
Make sure "javac.exe" must be inside your "C:\Program Files\Java\jdk1.7.0_45\bin"
Dont confuse with JRE and JDK both are totally different
if you dont have JDK pls download from this link http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html
reference thread for JDK VS JRE What is the difference between JDK and JRE?
Procedure:-
Install JDK
open cmd prompt
type "cd C:\Program Files\Java\jdk1.7.0_45\bin " press enter(path may change based on jdk version and 32bit and 64bit os version)
type "javac" press enter
its done
Now go and change your system environment variable path = C:\Program Files\Java\jdk1.7.0_45\bin
this will set the path permanently
回答3:
The JRE doesn't have javac - you need to download the JDK (Java Development Kit).
回答4:
First, you need to install the jdk, then add the path of bin folder of jdk in the path vaiable.
you can refer to this link
来源：https://stackoverflow.com/questions/18217853/javac-cannot-be-run-and-furthermore-does-not-seem-installed