== Why is this an issue?

``++StringBuffer++`` and ``++StringBuilder++`` instances that are ``++append++``ed but never ``++toString++``ed needlessly clutter the code, and worse are a drag on performance. Either they should be removed, or the missing ``++toString++`` call added.


=== Noncompliant code example

[source,java]
----
public void doSomething(List<String> strings) {

  StringBuilder sb = new StringBuilder();  // Noncompliant
  sb.append("Got: ");
  for (String str : strings) {
    sb.append(str).append(", ");
    // ...
  }
}
----


=== Compliant solution

[source,java]
----
public void doSomething(List<String> strings) {

  for (String str : strings) {
    // ...
  }
}
----
or

[source,java]
----
public void doSomething(List<String> strings) {

  StringBuilder sb = new StringBuilder();
  sb.append("Got: ");
  for (String str : strings) {
    sb.append(str).append(", ");
    // ...
  }

  LOGGER.info(sb.toString);
}
----


=== Exceptions

This rule ignores ``++StringBuffer++``s and ``++StringBuilder++``s that are passed as method arguments on the grounds that they are likely ``++toString++``ed there.


ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Remove this "String[Buffer|Builder]"; it is appended to but ".toString" is never called.


'''
== Comments And Links
(visible only on this page)

=== relates to: S3075

=== on 15 Jun 2015, 15:30:13 Ann Campbell wrote:
CodePro: Unused StringBuffer, UnusedStringBuilder

=== on 15 Jun 2015, 20:17:52 Nicolas Peru wrote:
Looks good

=== on 18 Sep 2015, 12:44:18 Ann Campbell wrote:
fyi [~tamas.vajk]

=== on 15 Oct 2015, 07:12:06 Tamas Vajk wrote:
Thanks [~ann.campbell.2]. I see one problem with this rule. We might pass the ``++StringBuilder++`` to a method, which internally calls ``++ToString++``, but at the declaring scope we won't know this. So if the ``++StringBuilder++`` is passed to a method we should not report on it. 

=== on 15 Oct 2015, 11:32:13 Ann Campbell wrote:
Thanks [~tamas.vajk], I've added an explicit exception.

endif::env-github,rspecator-view[]