Java class file

A Java class file is a file (with the .class filename extension) containing Java bytecode that can be executed on the Java Virtual Machine (JVM). A Java class file is usually produced by a Java compiler from Java programming language source files (.java files) containing Java classes (alternatively, other JVM languages can also be used to create class files). If a source file has more than one class, each class is compiled into a separate class file.'We used to go to lunch at a place called St Michael's Alley. According to local legend, in the deep dark past, the Grateful Dead used to perform there before they made it big. It was a pretty funky place that was definitely a Grateful Dead Kinda Place. When Jerry died, they even put up a little Buddhist-esque shrine. When we used to go there, we referred to the place as Cafe Dead. Somewhere along the line it was noticed that this was a HEX number. I was re-vamping some file format code and needed a couple of magic numbers: one for the persistent object file, and one for classes. I used CAFEDEAD for the object file format, and in grepping for 4 character hex words that fit after 'CAFE' (it seemed to be a good theme) I hit on BABE and decided to use it.At that time, it didn't seem terribly important or destined to go anywhere but the trash-can of history. So CAFEBABE became the class file format, and CAFEDEAD was the persistent object format. But the persistent object facility went away, and along with it went the use of CAFEDEAD - it was eventually replaced by RMI.Java SE 14 = 58 (0x3A hex),Java SE 13 = 57 (0x39 hex),Java SE 12 = 56 (0x38 hex),Java SE 11 = 55 (0x37 hex),Java SE 10 = 54 (0x36 hex),Java SE 9 = 53 (0x35 hex),Java SE 8 = 52 (0x34 hex),Java SE 7 = 51 (0x33 hex),Java SE 6.0 = 50 (0x32 hex),Java SE 5.0 = 49 (0x31 hex),JDK 1.4 = 48 (0x30 hex),JDK 1.3 = 47 (0x2F hex),JDK 1.2 = 46 (0x2E hex),JDK 1.1 = 45 (0x2D hex).For details of earlier version numbers see footnote 1 at The JavaTM Virtual Machine Specification 2nd editioneach element is a field_info structure defined in https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.5each element is a method_info structure defined in https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.6each element is an attribute_info structure defined in https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7 A Java class file is a file (with the .class filename extension) containing Java bytecode that can be executed on the Java Virtual Machine (JVM). A Java class file is usually produced by a Java compiler from Java programming language source files (.java files) containing Java classes (alternatively, other JVM languages can also be used to create class files). If a source file has more than one class, each class is compiled into a separate class file. JVMs are available for many platforms, and a class file compiled on one platform will execute on a JVM of another platform. This makes Java applications platform-independent. On 11 December 2006, the class file format was modified under Java Specification Request (JSR) 202.