Compiling trouble

Question

I am currently reading "Thinking in Java" 3rd edition by Bruce Eckel but am having trouble compiling his source code. I think it has something to do with path or classpath.
Here is the source and compiler errors.
import com.bruceeckel.simpletest.*;
class Number {
int i;
public class Assignment {
static Test monitor = new Test();
public static void main(String[] args) {
Number n1 = new Number();
Number n2 = new Number();
n1.i = 9;
n2.i = 47;
System.out.println("1: n1.i: " + n1.i +
", n2.i: " + n2.i);
n1 = n2;
System.out.println("2: n1.i: " + n1.i +
", n2.i: " + n2.i);
n1.i = 27;
System.out.println("3: n1.i: " + n1.i +
", n2.i: " + n2.i);
monitor.expect(new String[] {
"1: n1.i: 9, n2.i: 47",
"2: n1.i: 47, n2.i: 47",
"3: n1.i: 27, n2.i: 27"
} ///:~
G:\javaTutSource\c03>javac Assignment.java
g:\javaTutSource\com\bruceeckel\simpletest\Test.java:9: package java.util.regex
does not exist
import java.util.regex.*;
^
g:\javaTutSource\com\bruceeckel\simpletest\TestStream.java:9: package java.util.
regex does not exist
import java.util.regex.*;
^
g:\javaTutSource\com\bruceeckel\simpletest\Test.java:24: cannot resolve symbol
symbol : method getStackTrace ()
location: class java.lang.Throwable
new Throwable().getStackTrace()[1].getClassName();
^
g:\javaTutSource\com\bruceeckel\simpletest\TestExpression.java:6: package java.u
til.regex does not exist
import java.util.regex.*;
^
g:\javaTutSource\com\bruceeckel\simpletest\TestExpression.java:9: cannot resolve
symbol
symbol : class Pattern
location: class com.bruceeckel.simpletest.TestExpression
private Pattern p;
^
g:\javaTutSource\com\bruceeckel\simpletest\Test.java:44: cannot resolve symbol
symbol : constructor RuntimeException (java.io.IOException)
location: class java.lang.RuntimeException
throw new RuntimeException(e);
^
g:\javaTutSource\com\bruceeckel\simpletest\Test.java:67: cannot resolve symbol
symbol : constructor RuntimeException (java.lang.InterruptedException)
location: class java.lang.RuntimeException
throw new RuntimeException(e);
^
g:\javaTutSource\com\bruceeckel\simpletest\TestStream.java:50: cannot resolve sy
mbol
symbol : constructor RuntimeException (java.io.FileNotFoundException)
location: class java.lang.RuntimeException
throw new RuntimeException(e);
^
g:\javaTutSource\com\bruceeckel\simpletest\TestExpression.java:19: cannot resolv
e symbol
symbol : variable Pattern
location: class com.bruceeckel.simpletest.TestExpression
this.p = Pattern.compile(expression);
^
9 errors
Any help will be appreciated as i really want to lean java!!!

Answer 1

See if this helps with how packages are structured.
Assume that your programs are part of a package named myapp, which is specified by this first line in each source file: package myapp;
Also assume that directory (C:\java\work\) is listed in the CLASSPATH list of directories.
Also assume that all your source files reside in this directory structure: C:\java\work\myapp\
Then a statement to compile your source file named aProgram.java is:
C:\java\work\>javac myapp\aProgram.java
Explanation:
Compiling
A class is in a package if there is a package statement at the top of the class.
The source file needs to be in a subdirectory structure. The subdirectory structure must match the package statement. The top subdirectory must be in the classpath directory.
So, you generate a directory structure C:\java\work\myapp\ which is the [classpath directory + the package subdirectory structure], and place aProgram.java in it.
Then from the classpath directory (C:\java\work\) use the command: javac myapp\aProgram.java
Running
Compiling creates a file, aProgram.class in the myapp directory.
(The following is where people tend to get lost.)
The correct name now, as far as java is concerned, is the combination of package name and class name: myapp.aProgram (note I omit the .class) If you don't use this name, java will complain that it can't find the class.
To run a class that's NOT part of a package, you use the command: java SomeFile (assuming that SomeFile.class is in a directory that's listed in the classpath)
To run a class that IS part of a package, you use the command java myapp.aProgram (Note that this is analogous to the command for a class not in a package, you just use the fully qualified name)