Runtime Java error: Unsupported major.minor - UnsupportedClassVersionError

For the specific sample in this technote, the problem is that the executable was compiled with Java 1.5 (major 49) but the runtime is older, such as Java 1.4 (major.minor 48.0). Thus, the runtime Java 1.4 does not support running this program that was compiled with Java 1.5.
To determine if the runtime Java supports the level of Java with which the program was compiled, follow these steps:

1) Check the runtime version of Java.

java -version
For example, the output might look like this:
java version "1.4.2"
Java 2 Runtime Environment, Standard Edition (build 1.4.2)

2) Check the version of Java used to compile the Java class file that you are trying to run. There are several different ways to do this depending on the environment.

• If using Linux, you can use the command "file" to find out the version of Java used to compile the Java class file that you are trying to run, for example:
  $ file MQSample.class
  MQSample.class: cafe babe compiled Java class data, version 49.0
• For other operating systems, you can use the Java simple dis-assembler utility "javap" which is included with the Java SDK (but not included with the Java JRE). If the file is called JavaClassName.class, do NOT specify the *.class when invoking this tool:
  UNIX:
  javap -verbose JavaClassName | grep major
  major version: 50
  javap -verbose JavaClassName | grep minor
  minor version: 0
  
  Windows:
  javap -verbose JavaClassName | findstr major
  major version: 50
  javap -verbose JavaClassName | findstr minor
  minor version: 0
• You could compile and use the sample Java program mentioned in this article:
  
  Java API to find out the JDK version a class file is compiled for?

3) Use the following table to map the versions:
 

Major	Minor	Java platform version
45	3	1.1
46	0	1.2
47	0	1.3
48	0	1.4 Example: 1.4.x
49	0	1.5 Example: 1.5
50	0	1.6
51	0	1.7
52	0	1.8

For this example, there are 2 items to map:
a) Runtime Java version 1.4.x => major.minor is 48.0
b) Java class file shows "version 49.0", but it should be interpreted as: major.minor 49.0 => Java 1.5

Conclusion:
You are trying to run in a system that has Java 1.4 (major.minor 48) a Java class file that was compiled under Java 1.5 (major.minor 49), thus the error message:

(Unsupported major.minor version 49.0)

In other words, the runtime (major.minor 48) does not support major.minor 49.

Miscellaneous
The above table was obtained from:
http://www.rgagnon.com/javadetails/java-0544.html
and
http://en.wikipedia.org/wiki/Java_class_file
See "General layout" section, description comments for bytes 6 and 7

Java: Check the class version
The first 4 bytes are a magic number, 0xCAFEBABE, to identify a valid class file then the next 2 bytes identify the class format version (major and minor).