copying: deep vs shallow copy module (clone() traps, copy constructors, serialization copy, records, defensive copies, collection copies), 17 contract tests

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_017ic4b4X2xx7RrveVQU9R1N

copying/output/03-clone.txt

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+== 1. clone() does not call a constructor, and it is shallow ==
+  Team constructor ran for 'platform'
+  b == a                 : false
+  b.members == a.members : true
+  after a.members.add("meera"), b.members = [asha, ravi, meera]
+
+== 2. The fix: copy the mutable field inside clone() ==
+  c.members = [asha, ravi, meera]
+  d.members = [asha, ravi]
+
+== 3. Calling super.clone() without implementing Cloneable ==
+  CloneNotSupportedException: com.ankurm.copying.CloneDemo$ForgotCloneable
+
+== 4. Array clone() is shallow for nested arrays ==
+  gridCopy[0] == grid[0] : true
+  grid     = [[99, 2], [3, 4]]
+  gridCopy = [[99, 2], [3, 4]]
+
+== 5. ArrayList.clone() is shallow too ==
+  original.get(0) = abc-changed
+  same element object: true
+
+== 6. A parent clone() that uses 'new' breaks every subclass ==
+  ClassCastException: class com.ankurm.copying.CloneDemo$Animal cannot be cast to class com.ankurm.copying.CloneDemo$Dog (com.ankurm.copying.CloneDemo$Animal and com.ankurm.copying.CloneDemo$Dog are in unnamed module of loader 'app')