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According to the Java Language Specification \[[JLS 2005|AA. Java References#JLS 05]\] section 6.3.2 "Obscured Declarations":

A simple name may occur in contexts where it may potentially be interpreted as the name of a variable, a type or a package. In these situations, the rules of §6.5 specify that a variable will be chosen in preference to a type, and that a type will be chosen in preference to a package.

This implies that a variable can obscure a type or a package, and a type can obscure a package name. Shadowing on the other hand refers to masking of variables, fields, types, method parameters, labels and exception handler parameters in a subscope. Both these differ from hiding wherein an accessible member (typically non-private) that should have been inherited by a subclass is forgone in lieu of a locally declared subclass member that assumes the same name.

As a tenet, do not:

• Reuse the name of a superclass
• Reuse the name of an interface
• Reuse the name of a field defined in a superclass
• Reuse the name of a field that appears in the same method (in some different scope)
• Reuse the name of a field, type or another parameter across packages

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Well defined import statements do resolve these issues but may get confusing when the reused name is defined in a different package. Moreover, a common (and misleading) tendency is to include the import statements after writing the code. (many Many IDEs allow automatic inclusion of import statements as per the requirements.) . This can create even more ambiguity with respect to the names because if a custom type is found in the same package, no further searches are conducted for the package names that must be imported.

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package x;
public class A {
  void doLogic() { 
    // print 'A'  
  }  

  public static void main(String[] args) {
    // explicitly invokes doSequence() of class y.C and prints 'C'
    y.C.doSequence(); 
  }
}

package x;
public class B { /* ... */ }

package y; // different package
public class C extends x.B {  
  public void doSequence() { // now renamed
    // print 'C' 
  } 
}

Exceptions

SCP02-EX1: Reuse of names is permitted for trivial loop counter declarations in the same scope:

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Reusing names leads to code that is harder to read and maintain and may result in security weaknesses.

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