Problem supporting all the different versions of Java and libraries?

The Java language has undergone several changes. In addition to the language changes, much more dramatic changes have been made to the Java class library over the years, which have grown from a few hundred classes in JDK 1.0 to over three thousand in J2SE 6.0. We have also seen entire new APIs, such as Swing and Java2D, have been introduced. Many of the original JDK 1.0 classes and methods have been deprecated. A consequence of this is that companies have to support different versions of java. I in some organization this is becoming a problem. The result may be that an application server is supporting many different versions of Java from JDK 1.4 to 1.x. Each application may have different standard for use of Java, libraries, deployment etc.