1. Vulnerability Description

• Detect if the field is set to Null without @Nullable Annotation.

2. Vulnerability Countermeasure

• If a Null value is allowed, set @Nullable Annotation.

3. Sample Code

• Vulnerable Code

  private List<String> idList;
  public void reset() {
    idList = null;
    ...
  }

• Safe Code

  import javax.annotation.Nullable;
  ...
  private @Nullable List<String> idList;
  public void reset() {
    idList = null;
    ...
  }