Package
In this chapter you will learn:
- How to get package for a name
- How to get the package name
- How to get implementation title, vendor and version
- How to get the specification title, vendor and version
- How to get all packages
- How get the annotations for a package
Load package for a name
static Package getPackage(String name) finds a package by name
public class Main {
public static void main(String[] args) {
Package p = Package.getPackage("javax.swing");
System.out.print("Swing Version: ");
System.out.println(p.getSpecificationVersion());
// ja va2 s . c o m
p = Package.getPackage("java.awt");
System.out.print("AWT Version: ");
System.out.println(p.getSpecificationVersion());
}
}
The output:
Get the package name
String getName() returns the name of this package.
public class Main {
public static void main(String[] args) {
Package p = Package.getPackage("javax.swing");
//from ja v a2 s.co m
System.out.println(p.getName());
}
}
The output:
Get implementation title, vendor and version
String getImplementationTitle()returns the title of this package.String getImplementationVendor()returns the name of the organization, vendor.String getImplementationVersion()returns the version.
public class Main {
public static void main(String[] args) {
Package p = Package.getPackage("javax.swing");
/* java 2s . co m*/
System.out.println(p.getImplementationTitle());
System.out.println(p.getImplementationVendor());
System.out.println(p.getImplementationVersion());
}
}
The output:
Get the specification title, vendor and version
String getSpecificationTitle()returns the title of the specification.String getSpecificationVendor()returns the name of the organization, vendor.String getSpecificationVersion()returns the version number.
public class Main {
public static void main(String[] args) {
Package p = Package.getPackage("javax.swing");
//j ava 2 s . c o m
System.out.println(p.getSpecificationTitle());
System.out.println(p.getSpecificationVendor());
System.out.println(p.getSpecificationVersion());
}
}
The output:
Get all packages
static Package[] getPackages() gets all the packages currently known for the ClassLoader.
public class Main {
public static void main(String[] args) {
Package[] ps = Package.getPackages();
/*from j a va 2s. c o m*/
for(Package p:ps){
System.out.println(p);
}
}
}
The output:
Get the package's annotations
<A extends Annotation>A getAnnotation(Class<A> annotationClass)returns this element's annotation for the specified type if such an annotation is present, else null.Annotation[] getAnnotations()returns all annotations.Annotation[] getDeclaredAnnotations()returns all annotations that are directly present on this element.
public class Main {
public static void main(String[] args) {
Package[] ps = Package.getPackages();
/* j av a 2s. c o m*/
for(Package p:ps){
System.out.println(p.getAnnotations().length);
}
}
}
Next chapter...
What you will learn in the next chapter:
- How to get the length of an Array
- How to get value from an Array
- How to set value to an Array
- How to create new Array instance