How to Resolve com.sun.jdi.ObjectCollectedException During Variable Inspection in Eclipse?

What causes the com.sun.jdi.ObjectCollectedException when debugging and inspecting variables in Eclipse?

// Example snippet showcasing potential variable inspection issue
String someString = new String("Hello, World!");
// Assuming someString goes out of scope, may trigger ObjectCollectedException

The com.sun.jdi.ObjectCollectedException occurs in Eclipse when the debugger tries to access an object that has been garbage-collected. This typically happens if the object you're inspecting is no longer referenced in the current scope, making it inaccessible to the Java Debug Interface (JDI).

// Keeping a reference to the object to avoid collection issues
List<String> myStrings = new ArrayList<>();
myStrings.add("Example");
// Ensure references are maintained to prevent collection

Causes

• The inspected object has been garbage-collected because it is no longer referenced in the code.
• Variable scope issues, where the variable goes out of scope before inspection occurs.
• Using optimized code that may discard certain variable instances during runtime.

Solutions

• Ensure that the variables and objects you want to inspect are still in scope when the debugger pauses execution.
• Modify your code to retain references to objects that might otherwise be garbage-collected during debugging sessions.
• Adjust Eclipse's debugger settings or experimental features to better manage object lifecycles.

Mistake: Not checking if the variable is still in scope during debugging.

Solution: Always confirm that the variable is in the current scope before performing inspections.

Mistake: Assuming all objects remain in memory while the debugger is paused.

Solution: Understand that some objects might be eligible for garbage collection depending on the execution context.