What common mistake do developers make with Method injection, why does the mistake cause problems, and what is the safer approach?

What common mistake do developers make with Method injection, why does the mistake cause problems, and what is the safer approach? One recurring problem with method injection is applying it without understanding the boundary it protects. Resolving every dependency manually with new inside business classes, which makes configuration and testing harder. In addition, Dependencies can also be injected into certain framework-managed methods. Safer engineering approach: keep the responsibility in the correct layer, use the framework's supported API, validate and authorize inputs, avoid hidden side effects, and verify the behavior with tests.