The following code is rejected by the Java compiler(JDK 7 b76) if it deals with a class which name is an exotic identifier with a Java primitive type name inside:
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class #"int "{};
class A extends #"int"{};
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The output is:
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A.java:2: unexpected type
class A extends #"int"{};
                ^
  required: class
  found: int
1 error
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The compiler also fails if such names are used as type parameter bound:
class A<T extends #"int">{};
The exotic identifiers #"byte",#"int",... are also rejected if used in annotation names.

The code example and the ouput message:
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@interface #"int" {
    String s() default "default";
    int i() default 123;
}

@#"int"
class A {}
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A.java:6: incompatible types
@#"int"
 ^
  required: Annotation
  found: int
1 error
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