title: Can't do StringBuilder with Eclipse
body: <p>Recently I started to learn Java. When I try to do the following code:</p>
  
  <pre><code>public class Application {
  
      public static void main(String[] args) {
          StringBuilder sb = new StringBuilder("");
          sb.append("a");
      }
  }
  </code></pre>
  
  <p>I get the following errors:</p>
  
  <blockquote>
    <p>The type java.lang.CharSequence cannot be resolved. It is indirectly referenced from required .class files</p>
  </blockquote>
  
  <p>And</p>
  
  <blockquote>
    <p>Exception in thread "main" java.lang.Error: Unresolved compilation problem:
    The type java.lang.CharSequence cannot be resolved. It is indirectly referenced from required .class files</p>
  </blockquote>
  
  <p>at Application.main(Application.java:8) </p>