In Java 8, underscore (``++_++``) cannot be used as a parameter to a lambda, and by Java 9, it's a keyword. To ensure future portability (not to mention current readability), it should not be used now as an identifier.

== Noncompliant Code Example

[source,java]
----
private String _;  // Noncompliant
----

== Compliant Solution

[source,java]
----
private String foo;
----

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

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== Implementation Specification
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include::message.adoc[]

include::highlighting.adoc[]

'''
== Comments And Links
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include::../comments-and-links.adoc[]
endif::env-github,rspecator-view[]
