Todos os estilos de toString()
Utilizando a classe String:
return "FooClass [aFloat=" + aFloat + ", aString=" + aString + ", anInt=" + anInt + ", anObject=" + anObject + "]";
Ignorando alguns valores:
return "FooClass [aFloat=" + aFloat + ", "
+ (aString != null ? "aString=" + aString + ", " : "")
+ "anInt=" + anInt + ", "
+ (anObject != null ? "anObject=" + anObject : "") + "]";
Utilizando a classe StringBuilder/StringBuffer
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