LinkedHashMap is a Hash table and linked list implementation of the Map interface in the Java Standard library. This implementation provides a predictable iteration order, in contrast with the unspecified ordering provided by HashMap, which is normally the order in which keys were inserted into the map.
Questions tagged [linkedhashmap]
703 questions
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Linked Map in Java, being unequal if order of keys is different
Is there a Map in Java or 3rd-party libraries preserving insertion order (similar to LinkedHashMap) which would also check order of keys during comparison (equals() and hashCode() methods) ? So that Map(a => 1, b => 2) would be different from Map(b…

Zbynek Vyskovsky - kvr000
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Collection.unmodifiableMap iteration order
Does Colelction.unmodifiableMap safeguard the iteration order?
I was trying newMap.put(key,Collections.ModifiableMap(oldMap))
Then when I do newMap.get(key) and iterate, iterate order seems to change.
How can we protect the iterate order?

Chandra
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Does an ArrayList created from the keySet() of LinkedHashMap preserves the order of insertion?
I get data something like
{"Employee 1 of ABC", "ABCX"}, {"Employee 2 of ABC", "ABCY"},
{"Employee 3 of ABC", "ABCZ"}
from database through a RefCursor.
I have a case where I need to preserve the order in which data is read from the…

spiderman
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Efficient alternative to Map in Java, with regards to autoboxing?
I'm using a LinkedHashMap to store values of layers on a tile in a 2D game. Higher numbers are drawn over the lower numbers.
In my draw function, I iterate through the value set and draw each one. This means I'm unboxing values…

Audiocrow
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serialize/deserialize a LinkedHashMap (android) java
So i want to pass a LinkedHashMap to an intent.
//SEND THE MAP
Intent singlechannel = new Intent(getBaseContext(),singlechannel.class);
singlechannel.putExtra("db",shows1);//perase to
startActivity(singlechannel);
//GET THE…

weakwire
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LinkedHashMap$Entry cannot be cast to java.util.LinkedHashMap
I'm wrapped LinkedHashMap> into a List with;
List>> list = new ArrayList(mainCodesMap.entrySet());
which mainCodeMap is type of Map>
the…

quartaela
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what happens if we 'put' and new value to an already existing key in the Linkedhashmap
I have a fixed set of key value pairs with which I am initializing the LinkedHashMap.
Does the insertion order remain the same when I do a
LinkedHashMap.put(existingKey, newValue);
To be precise my question is, when we update a…

codeMan
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ConcurrentModificationException even with using Collections.sychronizedMap on a LinkedHashMap
I'm using a Map object in my class that I've synchronized with Collections.synchronizedMap() for a LinkedHashMap like so:
private GameObjectManager(){
gameObjects = Collections.synchronizedMap(new LinkedHashMap());
}
I'm…

mpellegr
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LinkedHashMap's impl - Uses Double Linked List, not a Single Linked List; Why
As I referred to the documentation of LinkedHashMap, It says, a double linked list(DLL) is maintained internally
I was trying to understand why a DLL was chosen over S(ingle)LL
The biggest advantage I get with a DLL would be traversing backwards,…

smc
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How to sort a LinkedHashMap by its value class's field?
I use the following lines to sort a LinkedHashMap, but not all items are sorted, anything wrong ?
LinkedHashMap statisticsMap;
// fill in the map ...
LinkedHashMap sortedStatisticsMap=new…

Frank
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Groovy/Grails LinkedHashMap behaving weirdly
I'm running into some confusing behaviour from LinkedHashMap in
grails 2.0.3. Running the following script in grails console:
def m = ["smart-1":[stuff:'asdf']]
println m.getClass()
def p = [id:1]
println m."smart-$p.id"
println…

Alex
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Soft reference LinkedHashMap in Java?
Is there softreference-based LinkedHashMap in Java? If no, has anyone got a snippet of code that I can probably reuse? I promise to reference it correctly.
Thanks.

His
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Java: Flat List
This issue seems to be pretty complex so here I'm posting this issue for any possible way to solve this.
I have list of Maps. I want again a list of map, but making sure the map is converted into some sort of hierarchy.
Original data:…

Jake
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How to convert LinkedHasMap Values into ArrayList/Array in right order?
I'm getting LinkedHashMap grades = courses.get(choise).getGrades();
I need to save the grades values in an array/arraylist.
I'm able to get values and keys in loop
String key = "";
String value = "";
for (Object o : grades.keySet()){
key =…

G. Dawid
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Getting 'Type mismatch: cannot convert from ArrayList> to List>' while instantiating a list of maps
List> recordMapList = new ArrayList>();
The above line gives the error:
Type mismatch: cannot convert from ArrayList> to List>
But the issue goes away if use HashMap instead of Map in the left hand…

DockYard
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