Java 反射 private final字段

java-final-field-reflect

Java 中对final 字段的修改，有很多黑魔法。

org/apache/commons/lang3/reflect

https://stackoverflow.com/questions/3301635/change-private-static-final-field-using-java-reflection/31268945#31268945

# System.in,out,err允许重定向

``` java
import java.lang.reflect.*;

public class EverythingIsTrue {
   static void setFinalStatic(Field field, Object newValue) throws Exception {
      field.setAccessible(true);

      Field modifiersField = Field.class.getDeclaredField("modifiers");
      modifiersField.setAccessible(true);
      modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);

      field.set(null, newValue);
   }
   public static void main(String args[]) throws Exception {      
      setFinalStatic(Boolean.class.getField("FALSE"), true);

      System.out.format("Everything is %s", false); // "Everything is true"
   }
}
```

# private static final 

# private final