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Cannot Set Static Final Java.lang.string

This will work for non-primitive fields as the value of an object reference can not be inlined at compile time. I think it would be safe to say that very few Java developers can remember the details of pre-JDK1.3.0. January 21, 2013 at 7:14 PM bjkail said... If the enum already * contains that particular value, then the value * is overwritten with our enum. weblink

Of course, we won't forget a best Java hacker friend - sun.misc.Unsafe class from Oracle JDK. Wrong way on a bike path? The JDK 1.1.8 JavaDocs for java.lang.reflect.Field had the following to say: If this Field object enforces Java language access control, and the underlying field is inaccessible, the method throws an IllegalAccessException. Why there are no approximation algorithms for SAT and other decision problems? http://stackoverflow.com/questions/3301635/change-private-static-final-field-using-java-reflection

more hot questions question feed lang-java about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life / Arts Culture / Recreation import java.lang.reflect.Field; public class FinalStaticFieldChange { /** Static fields of type String or primitive would get inlined */ private static final String stringValue = "original value"; private static final Object objValue Tagsalgorithms array avoiding worst practices BigDecimal binary serialization bitset book review boxing byte buffer collections cpu optimization data compression datatype optimization date dateformat double exceptions FastUtil FIX hashcode hashmap hdd hppc I totally agree with your comments.

The Java language specification says this: If a field is a constant variable (ยง4.12.4), then deleting the keyword final or changing its value will not break compatibility with pre-existing binaries by Please leave this field empty: Your name Your email address Your post Subject (Required) Please leave this field empty: Search Most read 1. AccessibleObject.setAccessible() will only succeed if the operation is allowed by the security context. « Previous • Trail • Next » Your use of this page and all the material on pages Not a good scenario!

I hope someone could help me. Ballpark salary equivalent today of "healthcare benefits" in the US? Why did Michael Corleone not forgive his brother Fredo? http://stackoverflow.com/questions/9391401/java-reflection-change-private-static-final-field-didnt-do-anything If we specify which classes the switch statements are, then these will be maintained at the same time.

Join them; it only takes a minute: Sign up Cannot change static final field using java reflection? Welcome to the 161st issue of The Java(tm) Specialists' Newsletter. I'd try to get the source and recompile (or even decompile/recompile) instead. –Bill K Jul 21 '10 at 17:07 System.out is a public static final field, but it can And ever since I know all this and I don´t use user defined class loader I use singletons without regret.

For example a field declared : private static String state;The field called "state" is a class variable, with the given keywords, it should only be accessible by other instance objects of It allows to circumvent visibility rules - which is step one - and interestingly it also implicitly allows change the value of instance fields reflectively, if they were marked as accessible. Typesetting text with math Draw a hollow square of # with given width Is there a word for turning something into a competition? Got really interested, so that what I became with: /** * @author Dmitrijs Lobanovskis * @since 03/03/2016. */ public class SomeClass { private final String str; SomeClass(){ this.str = "This is

pre-moderation This forum is moderated before publication: your contribution will only appear after being validated by an administrator. It may not work because a SecurityManager may be present, but even if it doesn't, depending on usage pattern, it may or may not work. It even says this: If a final field is initialized to a compile-time constant in the field declaration, changes to the final field may not be observed, since uses of that It would be fairly easy to find this field inside the anonymous inner class.

But really: Final fields? However use this very carefully, only when there's no other good solution. If the enum is switched several times in one class, then the inner class is only created once. check over here Lots of functionality!

asked 3 years ago viewed 6331 times active 3 years ago Upcoming Events 2016 Community Moderator Election ends Nov 22 Linked 296 Change private static final field using Java reflection 1 Why are LEDs in my home unaffected by voltage drop? This may have unexpected side-effects; for example, sometimes the original value will continue to be used by some sections of the application even though the value has been modified.

Problems with the examples?

Rogue WiFi Access point 3. How to be Recommended to be a Sitecore MVP Teenage daughter refusing to go to school Blender add rough/random surface Is it anti-pattern if a class property creates and returns a Access of fields was now checked at runtime, so we could not use the class swapping trick to access private fields. public class Main { // value is not known at compile time, so not inlined public static final boolean FLAG = Boolean.parseBoolean("false"); static void setFinalStatic(Class clazz, String fieldName, Object newValue) throws

Iptables firewall versus nmap and hping3 2. If a final field is initialized to a compile-time constant in the field declaration, changes to the final field may not be observed, since uses of that final field are replaced Heinz M. this content offset could be obtained with Unsafe.objectFieldOffset( Field ) for instance fields and Unsafe.staticFieldOffset( Field ) for static fields.

In my last newsletter, I invited you to say "hello" with yahoo messenger. Do you remember running Java for the first time and getting this error: "Unable to initialize threads: cannot find class java/lang/Thread"? I decided to rather not publish my yahoo ID on my website, imagine if 450'000 TheServerSide readers were to suddenly decide that they all wanted to be my friend ;-) So, Also, most articles are now published under a free Creative Common license 2010-2016 Sevagas Archives | Log in | Contact Sebastian Zarnekow's Blog Thoughts of a passionate programmer Monday, January 21,

Secondly, we change the modifiers field value inside the Field object instance to not be final. Why there are no approximation algorithms for SAT and other decision problems? What is the total sum of the cardinalities of all subsets of a set? This all started with an email from Ken Dobson of Edinburgh, which pointed me in the direction of the sun.reflect.ConstructorAccessor, which he claimed could be used to construct enum instances.

Here is how we could use it to test our Human class: import junit.framework.TestCase; public class HumanTest extends TestCase { public void testSingingAddingEnum() { EnumBuster buster = new EnumBuster(HumanState.class, Human.class); try If we read section 9.1.1 carefully, we see that we should only modify final fields as part of our construction process. The JVM uses this guarentee to maintain consistency in various places (eg inner classes referencing outer variables). These examples shows that Java data access security is guaranteed by the language keywords, however this statement is not true because of Java "reflection".Reflection is a Java feature that allows a

Java 5 - "final" is not final anymore Narve Saetre from Machina Networks in Norway sent me a note yesterday, mentioning that it was a pity that we could change the You may also update final and static final fields using sun.misc.Unsafe. more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed NEW: We have revised our "Advanced Topics" course, covering Reflection, Java NIO, Data Structures, Memory Management and several other useful topics for Java experts to master. 2 days of extreme fun

Embed Embed this gist in your website. Inequality caused by float inaccuracy Why do the cars die after removing jumper cables I changed one method signature and broke 25,000 other classes. Example : Disable Java security The best example to show that reflection is a dangerous feature is to show that all the security mechanisms of Java, relying on the security manager, Are there continuous functions for which the epsilon-delta property doesn't hold?

Rewiring Enum Switches The next idea was to rewire the actual switch statement's $SwitchMap$HumanState field. Are there any issues with multi-threading? It would involve something like: Constructor cstr = clazz.getDeclaredConstructor( String.class, int.class ); ReflectionFactory reflection = ReflectionFactory.getReflectionFactory(); Enum e = reflection.newConstructorAccessor(cstr).newInstance("BLA",3); However, if we just do that, we end up with an