Question

I tried to include android.jar into Java project, remove JRE from Build Path and run this code. It throws Runtime exception. Why?

Exception in thread "main" java.lang.RuntimeException: Stub!
    at android.content.ContentValues.<init>(ContentValues.java:5)
    at JarTest.main(JarTest.java:5)

public class JarTest {
    public static void main(final String[] args) {
        final ContentValues values = new ContentValues();
        values.put("test", "test");
        System.out.println(values);
    }
}

Why is ContentValues used only in Android environment?

Answer 1

The android.jar in the SDK only contains stub implementations of the SDK classes, not the real implementations that are found on the devices (or emulator). The jar just provides the class metadata so that your apps that reference the SDK classes will build properly.

You can’t create any project that references the android.jar that will run outside an Android device.