How many classes are there in Java standard edition?

Question

I am curious how many classes are there in Java standard library. Perhaps someone knows an approximate number?

Answer 1

By counting entries in the 'all classes' frame of the javadoc API:

• 4569 in java 14
• 4545 in java 13
• 4433 in java 12
• 4411 in java 11
• 6002 in java 10
• 6005 in java 9
• 4240 in java 8
• 4024 in java 7
• 3793 in java 6
• 3279 in java 5.0
• 2723 in java 1.4.2*
• 1840 in java 1.3.1*

* Javadocs prior to 5.0 are now offline.

Answer 2

According to the API documentation 3793 including abstract classes and interfaces.

Answer 3

I counted 17,338 in Java 6.0. My methodology:

jar -tf ${JAVA}/jre/lib/rt.jar > rtjar.txt
emacs rtjar.txt

I deleted two lines related to the manifest (and thus not representing a class). I believe that the other lines all refer to classes, but I did not do an exhaustive check. Then I went to the bottom of the file and emacs told me that there 17,338 lines.

This includes stuff like: java/io/ObjectOutputStream$1.class.