Who is Jimmy Snyder from Extremely Loud and Incredibly Close and what is their importance?

Oskar Schell's classmate who plays Hamlet in the abbreviated presentation of the Shakespearean play, Jimmy is a bully. Oskar pictures beating him to a bloody pulp during the final night's performance, after verbally abusing him. Jimmy is sent to the principal's office for calling Oskar weird during his Hiroshima presentation, and on the playground threatens to beat Oskar up unless he admits his Mom is a whore.