Java Reference
In-Depth Information
Note The compiler automatically imports the String class and other types from
the java.lang package, which is why it is not necessary to qualify String with
java.lang .
Searching for Packages and Types
Newcomers to Java who first start to work with packages often become frustrated by
“no class definition found” and other errors. This frustration can be partly avoided by
understanding how the JVM searches for packages and types.
of the JVM. Furthermore, there are two different forms of search.
Compile-Time Search
in the method call, for example).
The compiler first searches the Java platform packages (which contain class library
types).Itthensearchesextensionpackages(forextensiontypes).Ifthe -sourcepath
command-lineoptionwasspecifiedwhenstartingtheJVM(via javac ),thecompiler
searches the indicated path's source files.
Note Javaplatformpackagesarestoredin rt.jar andafewotherimportantJAR
files. Extension packages are stored in a special extensions directory named ext .
rent directory is searched. Ifnopackage matches orthe type still cannot be found,the
compiler reports an error. Otherwise, the compiler records the package information in
the classfile.
Note Theuserclasspathisspecifiedviathe -classpath optionusedtostartthe
JVM or, if not present, the CLASSPATH environment variable.
Search WWH ::

Custom Search