[Solved] Examine the following Spring component:@Component public class Processor { @Autowired private Helper helper; public Processor() { System.out.println(helper.... } }What is the issue with this code? | Spring Boot

Spring Boot - Inversion of Control and Dependency Injection

Examine the following Spring component:

@Component
public class Processor {
  @Autowired
  private Helper helper;

  public Processor() {
    System.out.println(helper.process());
  }
}

What is the issue with this code?

AThe constructor should be annotated with <code>@Autowired</code>.

BThe <code>@Component</code> annotation is missing on the Helper class.

CThe <code>helper</code> field is not injected before the constructor runs, causing a NullPointerException.

DThe <code>process()</code> method must be static.

Step-by-Step Solution

Solution:

Step 1: Understand injection timing
Field injection happens after the constructor completes.
Step 2: Constructor uses uninitialized field
Calling helper.process() in the constructor causes NullPointerException because helper is null.
Step 3: Correct approach
Use constructor injection or avoid using injected fields in constructor.
Final Answer:
The helper field is not injected before the constructor runs, causing a NullPointerException. -> Option C
Quick Check:
Are fields injected before constructor execution? No [OK]

Quick Trick: Field injection happens after constructor runs [OK]

Common Mistakes:

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