If you've ever wondered which JDK version corresponds to class file version 69, here’s a simple and easy way to get the correct answer without looking up a Java version – class file version mapping table:

 

Java Version = Class File Version - 44

 

This simple math is easy for everyone because the number 44 is very easy to remember: it's the last two numbers of the year before World War II ended (1944) - year 44th in the last century.

Let's apply this formula to a Java class file with version 69:

Java Version = 69 - 44 = 25

 

That means the class file corresponds to Java 25. Simple enough, right?

Notes: this formula applies only for Java version 5 or later.

Similarly, if you want to know the exact class file version that corresponds to a specific Java version, use this formula:

Class File Version = Java Version + 44

 

For example, if you’re using JDK 8, the class file version should be 8 + 44 = 52. No rocket science, right?

Anyway, if this simple math doesn't work for you, you can always refer to the following table.

 

Java Version – Class File Version Mapping:

Java / JDK Version	Class File Version
Java 27	71.0
Java 26	70.0
Java 25	69.0
Java 24	68.0
Java 23	67.0
Java 22	66.0
Java 21	65.0
Java 20	64.0
Java 19	63.0
Java 18	62.0
Java 17	61.0
Java 16	60.0
Java 15	59.0
Java 14	58.0
Java 13	57.0
Java 12	56.0
Java 11	55.0
Java 10	54.0
Java 9	53.0
Java 8	52.0
Java 7	51.0
Java 6	50.0
Java 5	49.0
Java 1.4	48.0
Java 1.3	47.0
Java 1.2	46.0
Java 1.1	45.3
Java 1.0	45.0

 

For Java 1.0, the class file version is the year (last two numbers) when World War II ended (45). Then incremented by one for each Java version 1.2 (46), 1.3 (47) and 1.4 (48).

 

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