What is classpath hell and is/was it really a problem for Java?

Question

What is classpath hell and is/was it really a problem for Java?

Answer 1

I think "classpath hell" refers to the time when the classpath of a Java app could only be set by using the CLASSPATH environment variable. This led to many applications requiring changes to the global system configuration (different for each OS), version conflicts between applications, and general confusion.