Given the scenario: This class is intended to allow users to write a series of messages, so that each message is identified with a timestamp and the name of the thread that wrote the message:public class Logger { private StringBuilder contents = new StringBuilder(); public void log(String message) { contents.append(System.currentTimeMillis()); contents.append(": "); contents.append(Thread.currentThread().getName()); contents.append(message); contents.append("
"); } public String getContents() { return contents.toString(); }}How can we ensure that instances of this class can be safely used by multiple threads?

Question

Given the scenario: This class is intended to allow users to write a series of messages, so that each message is identified with a timestamp and the name of the thread that wrote the message:public class Logger {  private StringBuilder contents = new StringBuilder();  public void log(String message) {   contents.append(System.currentTimeMillis());   contents.append(": ");   contents.append(Thread.currentThread().getName());   contents.append(message);   contents.append("
");  }  public String getContents() { return contents.toString(); }}How can we ensure that instances of this class can be safely used by multiple threads?

Examsnet · Accepted Answer

Correct Answer is : Synchronize both log() and getContents().

Multi Threading