What does John 14:22 mean?

Modern culture, especially in the west, has almost entirely abandoned using the name Judas, thanks to the reputation of Judas Iscariot (John 13:2). During the lifetime of the disciples, however, it was a common name. This verse notes another disciple named Judas, likely the person also called Thaddeus in Mark 3:18 and Matthew 10:3. In Greek, this name is Iouda, which is also the name of the author of the book of Jude. Just as names like "Mary" were extremely common among women (Luke 24:10; Matthew 27:61), names like John and Judas were common among men.

This man's confusion is understandable. At this point, the disciples don't fully understand everything Jesus has told them. Modern readers have the benefit of hindsight. We read Jesus' words knowing exactly what's going to happen, and how it will all work out. These men understand the broad concepts, but haven't seen the specific details. So when Jesus says that soon the world will not be able to see Him, but these men will (John 14:19), the meaning is not clear.