“Cannot find symbol” for my own class

问题:

I do not have a %CLASSPATH% set up. As I understand, this should not be a problem because Javac will assume a classpath of the current directory.

As you can see below, javac is unable to find my Case class even though it's in the same exact directory. Any thoughts on why this is happening? This code works fine when I use Eclipse.

C:\Documents and Settings\joep\My Documents\GCJ\src\codejam2011\Round0\D>dir /B
Case.class
Case.java
EntryPoint.java

C:\Documents and Settings\joep\My Documents\GCJ\src\codejam2011\Round0\D>javac EntryPoint.java

EntryPoint.java:16: cannot find symbol
symbol  : class Case
location: class codejam2011.Round0.D.EntryPoint
                ArrayList<Case> cases = new ArrayList<Case>();
                          ^
EntryPoint.java:16: cannot find symbol
symbol  : class Case
location: class codejam2011.Round0.D.EntryPoint
                ArrayList<Case> cases = new ArrayList<Case>();
                                                      ^
EntryPoint.java:24: cannot find symbol
symbol  : class Case
location: class codejam2011.Round0.D.EntryPoint
                                cases.add(new Case(new Integer(count), line));
                                              ^
3 errors

C:\Documents and Settings\joep\My Documents\GCJ\src\codejam2011\Round0\D>

Update 1:

After trying to compile from my package root (src), I get a new error (even after deleting the Case.class file)

C:\Documents and Settings\joep\My Documents\GCJ\src>javac -cp . codejam2011/Round0/D/EntryPoint.java

codejam2011\Round0\D\EntryPoint.java:16: cannot access codejam2011.Round0.D.Case

bad class file: .\codejam2011\Round0\D\Case.java
file does not contain class codejam2011.Round0.D.Case
Please remove or make sure it appears in the correct subdirectory of the classpath.
                ArrayList<Case> cases = new ArrayList<Case>();
                          ^
1 error

C:\Documents and Settings\joep\My Documents\GCJ\src>

Update 2: It appears to be grabbing the Case.java file from a different package.

C:\Documents and Settings\joep\My Documents\GCJ\src>javac -d ../classes codejam2011\Round0\D\*.java

.\codejam2011\Round0\D\Case.java:4: duplicate class: codejam2011.Round0.C.Case
public class Case
       ^
codejam2011\Round0\D\EntryPoint.java:16: cannot access codejam2011.Round0.D.Case

bad class file: .\codejam2011\Round0\D\Case.java
file does not contain class codejam2011.Round0.D.Case
Please remove or make sure it appears in the correct subdirectory of the classpath.
                ArrayList<Case> cases = new ArrayList<Case>();
                          ^
2 errors

C:\Documents and Settings\joep\My Documents\GCJ\src>

回答1:

You need to compile from the package root, not from inside the package.

So, cd to the src folder and compile from there.

javac -cp . codejam2011/Round0/D/EntryPoint.java

---

Update: as per your new problem, you need to recompile Case.java the same way. It was apparently compiled the same wrong way (from inside the package).

回答2:

If the problem is not yet solved by compiling from the package root directory (see the other answers):

• make sure all the source files contain classes with names corresponding to their file name
• make sure all the source files contain a package statement corresponding to their position in the source file hierarchy
• delete all your .class files before compiling (this should only be necessary once, if you checked everything else).

Thus, if the file is codejam2011\Round0\D\Case.java, it should contain package codejam2011.Round0.D; as the first declaration, and then public class Case { ... }. Also, make sure there is no other source file containing this package and class declaration.

From your error message, it looks like the package statement is package codejam2011.Round0.C; instead (and you also have a class Case in the real codejam2011.Round0.C package).

回答3:

You are in the wrong directory for compiling.

location: class codejam2011.Round0.D.EntryPoint

That tells me, that your package is codejam2011.Round0.D (which is against the convention (all lowercase) but beside the point ...

cd to the parent dir of codejam2011, which is src, isn't it?

javac codejam2011\Round0\D\EntryPoint.java

might do the trick.

Often you have a directory for compiled classes, like 'bin' or 'classes'. To produce the classes there, use -d (destination):

javac -d ../classes codejam2011\Round0\D\EntryPoint.java

回答4:

I have similar issue, it might not apply to all cases, but what I have done is remove .gradle, build and out folder and rebuild the program again.