An indexOf or lastIndexOf call with a single letter String can be made more performant by switching to a call with a char argument.

Noncompliant Code Example

String myStr = "Hello World";
// ...
int pos = myStr.indexOf("W");  // Noncompliant
// ...
int otherPos = myStr.lastIndexOf("r"); // Noncompliant
// ...

Compliant Solution

String myStr = "Hello World";
// ...
int pos = myStr.indexOf('W');
// ...
int otherPos = myStr.lastIndexOf('r');
// ...