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The try-finally statement guarantees the execution of a specific code block (the finally clause) regardless of whether an exception is thrown or a control flow transfer occurs within the associated try block. It ensures that finalization logic runs unconditionally before the current scope is exited.

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Syntax

try {
  // Protected code block
  // May throw an exception or return
} finally {
  // Unconditional code block
  // Always executes
}

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Execution Mechanics

The execution flow follows strict precedence rules depending on the outcome of the try block:
  1. Normal Completion: If the try block executes without errors, the finally block executes immediately after the last statement of the try block.
  2. Exception Propagation: If an exception is thrown within the try block and no catch clause is present:
    • Execution of the try block halts immediately.
    • The finally block executes.
    • After the finally block completes, the exception resumes propagation up the call stack.

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Interaction with Control Flow

The finally block intercepts control flow statements (return, break, continue, rethrow) initiated within the try block. The finally block executes before the control transfer completes.

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Return Statement Example

If a return statement is encountered in the try block, the return value is calculated, but the method exit is paused until the finally block executes. 
String demoFlow() {
  try {
    print('1. Try block start');
    return 'Result'; // Execution pauses here
  } finally {
    print('2. Finally block executes');
  }
}
// Output:
// 1. Try block start
// 2. Finally block executes
// Returns: 'Result'

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Chained with Catch

When combined with on or catch, the finally block remains the last step in the sequence. 
try {
  throw Exception('Critical Failure');
} catch (e) {
  print('Exception handled');
} finally {
  print('Cleanup executed');
}
Execution Order:
  1. Exception thrown in try.
  2. Control transfers to catch.
  3. catch block completes.
  4. finally block executes.
  5. Execution continues after the finally block.
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