i have made an application in JDK7, but the jre6 is still using in the market, and if i send my jar file to someone with jre6, it wont work, is there a way that application
You can use System.getProperty(String key); method with "java.version" as key.
"java.version"
String version = System.getProperty("java.version");
Example output:
1.6.0_30
The available keys can find at here.