1Z0-829 Java 17 Access, Immutability, and Object Contracts Guide
April 13, 2026
Study 1Z0-829 Java 17 Access, Immutability, and Object Contracts: key concepts, common traps, and exam decision cues.
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This chapter is where “clean design” becomes exam-scored behavior. If access or object contracts are wrong, the snippet often fails before business logic matters.
Object-contract map
If the stem is mainly about…
Better first instinct
package boundaries and imports
access level and package relationship matter first
safe immutable design
check for defensive copies and mutable components
equality in collections or comparisons
object contract behavior matters more than printing
What the exam is really testing
If the code shows…
Strong reading
package-private access
compile-time boundary issue
“immutable” class with mutable field contents
true immutability may be broken
equals without hashCode reasoning
contract consistency is likely the point
Common traps
Trap
Better rule
thinking final alone makes an object immutable
contained mutable state still matters
using identity intuition where equality is under test