== Why is this an issue?

Looking for a given substring starting from a specified offset can be achieved by such code: ``++str.substring(beginIndex).indexOf(char1)++``. This works well, but it creates a new ``++String++`` for each call to the ``++substring++`` method. When this is done in a loop, a lot of ``++Strings++`` are created for nothing, which can lead to performance problems if ``++str++`` is large.


To avoid performance problems, ``++String.substring(beginIndex)++`` should not be chained with the following methods:

* ``++indexOf(int ch)++``
* ``++indexOf(String str)++``
* ``++lastIndexOf(int ch)++``
* ``++lastIndexOf(String str)++``
* ``++startsWith(String prefix)++``

For each of these methods, another method with an additional parameter is available to specify an offset.

Using these methods will avoid the creation of additional ``++String++`` instances.
For indexOf methods, adjust the returned value by subtracting the substring index parameter to obtain the same result.


=== Noncompliant code example

[source,java]
----
str.substring(beginIndex).indexOf(char1); // Noncompliant; a new String is going to be created by "substring"
----


=== Compliant solution

[source,java]
----
str.indexOf(char1, beginIndex) - beginIndex; // index for char1 not found is (-1-beginIndex)
----

include::../rspecator.adoc[]