R

readObject, serialization methods, 449–452

reference variables

assigning, 188–190

casting, 112–115, 155

declaring, 51

equality (= = and !=) operators for, 281–282

key points regarding, 95

reassigning, 248–249

reference variables assigned to another reference variable, 200–203

values assigned to, 277

widening and overloading, 240–243

references

default values, 193

isolating a reference, 249–250

rules for classes referencing themselves, 643

regular expressions (regex), 472

relational (<,< =, >, > =, = =, !=) operators

comparison operators, 279

equality operators, 280–283

overview, 278–279

two-minute drill, 299

relative paths, 771–772

remainder (%) operator, 287

renameTo(), files and directories, 442

replace(), 422

return types, 122–126

covariant returns, 123–124

on overloaded methods, 122–123

overridden methods and, 123–124

overview, 122

returning a value, 124–126

two-minute drill, 155

reverse(), StringBuffer methods, 427

run(), thread methods, 676

Runnable interface, 678

runtime

disabling assertions at, 378

enabling assertions at, 377–378

"An exception occurs at runtime," 338

runtime protection and generics, 580–581

RuntimeException, 355, 361–362

RuntimeException, 355, 361–362