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  1. import java.util.Collection;
  2. import java.util.Map;
  3. import java.lang.reflect.*;
  4.  
  5. class A {
  6.     public A[] as;
  7.     public Collection<String> cs;
  8.     public Map<String, Integer> msi;
  9.     private String s;
  10.     protected int i;
  11. }
  12.  
  13. class Inspector {
  14.     public static void inspect(Class<?> clazz) {
  15. 	try {
  16. 	    System.out.println("Inspecting class " + clazz.getSimpleName() + ":");
  17. 	    Field[] fields = clazz.getDeclaredFields();
  18. 	    for (Field f : fields) {
  19. 		describe(f);
  20. 	    }
  21. 	} catch (Exception e) {
  22. 	    e.printStackTrace();
  23. 	}
  24.     }
  25.  
  26.     private static void describe(Field f) throws Exception {
  27. 	describeModifiers(f);
  28. 	Type t = f.getGenericType();
  29. 	describeType(t);
  30. 	System.out.println(" " + f.getName());
  31.     }
  32.  
  33.     private static void describeModifiers(Field f) {
  34. 	int modifiers = f.getModifiers();
  35. 	if (Modifier.isPublic(modifiers)) {
  36. 	    System.out.print(" public ");
  37. 	}
  38. 	if (Modifier.isPrivate(modifiers)) {
  39. 	    System.out.print(" private ");
  40. 	}
  41. 	if (Modifier.isProtected(modifiers)) {
  42. 	    System.out.print(" protected ");
  43. 	}
  44. 	// add more if you like
  45.     }
  46.  
  47.     private static void describeType(Type type) {
  48. 	if (type instanceof ParameterizedType) {
  49. 	    ParameterizedType pt = (ParameterizedType) type;
  50. 	    Type[] args = pt.getActualTypeArguments();
  51. 	    System.out.print(pt.getRawType());
  52. 	    System.out.print("<");
  53. 	    boolean atBegin = true;
  54. 	    for (Type t : args) {
  55. 		if (atBegin) {
  56. 		    atBegin = false;
  57. 		} else {
  58. 		    System.out.print(", ");
  59. 		}
  60. 		describeType(t);
  61. 	    }
  62. 	    System.out.print("> ");
  63.  
  64. 	} else if (type instanceof GenericArrayType) {
  65. 	    GenericArrayType arrType = (GenericArrayType) type;
  66. 	    describeType(arrType.getGenericComponentType());
  67. 	    System.out.println("[] ");
  68. 	} else if (type instanceof Class) {
  69. 	    Class<?> clazz = (Class) type;
  70. 	    System.out.print(clazz.getSimpleName());
  71. 	}
  72. 	// a lot of more interesing stuff can be done here
  73.     }
  74. }
  75.  
  76. class Main {
  77.  
  78.     public static void main(String... args) {
  79. 	Inspector.inspect(A.class);
  80.     }
  81. }
Success #stdin #stdout 0.03s 245632KB
comments (?)
stdin 
Standard input is empty
stdout 
Inspecting class A:
 public A[] as
 public interface java.util.Collection<String>  cs
 public interface java.util.Map<String, Integer>  msi
 private String s
 protected int i
https://ideone.com/C3J0i
language:
Java (HotSpot 12)
created:
14 years ago
visibility:
public

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