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1. Top results related to 2 types of dictionary in java code

   • Dictionary of ArrayLists in Java

     Top Answer

     Answered Jun 05, 2012 · 2 votes

     Instead of ArrayList grades; you'd have to use ArrayList grades = new ArrayList();

     Yet better: ArrayList<Float> grades = new ArrayList<Float>(); //or use Double or Number

     Note that unlike C or C++ creating a variable doesn't create the object as well. In C++ you could imagine your code as ArrayList* grades; i.e. you'd just create the reference/pointer here.

     Additional thoughts:

     • Dictionary studentGrades; this will be initialized to null.
     • public void main(String[] args) that's not a valid main function since it would have to be static
     • if you have a public static void main(String[] args) you can't use this since you don't have an object instance in the static context
     • You can't instantiate Dictionary since it is abstract. Use one of its subclasses, e.g. new Hashtable<String, List<Float>>(), or a map, e.g. Map<String, List<Float> dictionary = new HashMap<String, List<Float>>();
     • Note that local primitive variables are also not initialized, so this could give you an error too: boolean res; In Java only class members are initialized, local variables are not.

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     1/5

   • Types of References in Java

     In Java there are four types of references differentiated on the way by which they are garbage collected.

     • Strong References
     • Weak References
     • Soft References
     • Phantom References

     Prerequisite: Garbage Collection

     MyClass obj = new MyClass (); -

     obj = null;//'obj' object is no longer referencing to the instance. So the 'MyClass type object is now available for garbage collection. -

     // Java program to illustrate Strong reference class Gfg {     //Code.. } public class Example {     public static void main(String[] args)     {          //Strong Reference - by default         Gfg g = new Gfg();                       //Now, object to which 'g' was pointing earlier is          //eligible for garbage collection.         g = null;      } }  -

     If JVM detects an object with only weak references (i.e. no strong or soft references linked to any object object), this object will be marked for garbage...

     • This type of reference is used in WeakHashMap to reference the entry objects .
     • If JVM detects an object with only weak references (i.e. no strong or soft references linked to any object object), this object will be marked for garbage collection.

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     2/5

   • Types of Interfaces in Java

     In Java, an interface is a reference type similar to a class that can contain only constants, the method signatures, default methods, and static methods, and its Nested types. In interfaces, method bodies exist only for default methods and static methods. Writing an interface is similar to writing to a standard class. Still, a class describes the attributes and internal behaviors objects, and an interface contains behaviors that a class implements. On the other side unless the class that implements the interface is purely abstract and all the interface methods need to be defined in that given usable class.

     An interface is Similar To a Class In Following Ways:

     • An interface can contain any number of methods in that interface.
     • An Interface can have constant values, which are implicitly defined as public static final.

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     3/5

   • Types of Classes in Java

     A class is a blueprint in the Java programming language from which an individual object can be built. In Java, we may declare a class by using the class keyword. Class members and functions are declared simply within the class. Classes are required for the creation of Java programs. The object-oriented paradigm (OOP) allows users to describe real-world objects. Also, a class is sometimes known as a user-defined data type. The following components make up a class declaration:

     • Modifiers
     • Class name
     • Keywords
     • The class body within curly brackets {}.

     Class in Java  

     1. Class is a set of object which shares common characteristics/ behavior and common properties/ attributes. 2. Class is not a real world entity. It is just a template or blueprint or prototype from which objects are created. 3. Class does not occupy memory. 4. Class is a group of variables of different data types and group of methods.

     A class in java can contain: • data member • method • constructor • nested class and  • interface

     Syntax to declare a class:...

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     4/5

   • How to Validate Canadian postal Code in Java? Checking for 2 types of input? ex: accepting A1A1A1 and A1A 1A1

     Top Answer

     Answered Oct 30, 2016 · 1 votes

     The easy solution is: simply treat the two kinds of input the same way when processing them internally. Meaning:

     • Create one method that validates a 6-char potential ZIP code
     • But before calling that method, you check if your input contains a space as 4th character, and if so, you simply remove that space before giving it as parameter to your validation method.

     But keep in mind: you probably want to keep the original string around - if you intend to give back "A1A A2A" later on. Of course, if you decide that users can enter ZIPs in two ways, but that they should get back "unified" format later on, then you can make that "space-dropping" thing permanent.

     EDIT: you create a method

     public boolean isValid(String zipCode) { that returns TRUE for valid zipcodes that have 6 (SIX!) chars and no spaces-

     and another method

     public String normalizeZipCode(String incoming) { return incoming.replaceAll("\\s+","");}-

     To be used like:

     String zip1 = "A1A 1A1";String zip2 = "A1A1A1";-String normalizedZip1 = normalizeZipCode(zip1);String normalizedZip2 = normalizeZipCode(zip2);-System.out.println(isValid(normalizedZip1));System.out.println(isValid(normalizedZip2));-

     The simple idea: if one format contains spaces, then just remove those spaces prior validation. In other words: you allow the user to enter data in two formats; but internally, you make sure that any usage of the second format is simply avoided, by turning it into the format that comes without spaces.

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     5/5

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2. www.geeksforgeeks.org › java-util-dictionary-classJava.util.Dictionary Class in Java - GeeksforGeeks

   www.geeksforgeeks.org › java-util-dictionary-class

   • Cached

   Apr 9, 2023 · The java.util.Dictionary class in Java is an abstract class that represents a collection of key-value pairs, where keys are unique and are used to access the values. It was part of the Java Collections Framework introduced in Java 1.2 but has been largely replaced by the java.util.Map interface since Java 1.2.

3. docs.oracle.com › api › javaDictionary (Java Platform SE 8 ) - Oracle

   docs.oracle.com › api › java

   • Cached

   The Dictionary class is the abstract parent of any class, such as Hashtable, which maps keys to values. Every key and every value is an object. In any one Dictionary object, every key is associated with at most one value. Given a Dictionary and a key, the associated element can be looked up.

4. stackoverflow.com › questions › 4579683Implement dictionary using Java - Stack Overflow

   stackoverflow.com › questions › 4579683

   • Cached

   Dec 18, 2012 · The dictionary ADT models a searchable collection of key-element entries. Multiple items with the same key are allowed. Applications: word-definition pairs. Dictionary ADT methods: find (k): if the dictionary has an entry with key k, returns it, else, returns null.

   Code sample

   private List<Entry<K, V>> set;

   public Dictionary() {

     this.set = new LinkedList<Entry<K, V>>();

   }

   public Entry<K, V> find(K key) {...

   See more on stackoverflow

5. www.toolsqa.com › java › dictionary-classDictionary Class in Java | Dictionary usage in Java - Tools QA

   www.toolsqa.com › java › dictionary-class

   • Cached

   Jul 27, 2021 · In Java, a Dictionary is an abstract class that maps keys to values. Both keys and values can be objects of any type but not null. An attempt to insert either a null key or a null value to a dictionary causes a NullPointerException exception.

6. thelinuxcode.com › create-a-dictionary-in-javaThe Complete Guide to Effectively Using Dictionaries in Java

   thelinuxcode.com › create-a-dictionary-in-java

   • Cached

   Dec 27, 2023 · Dictionaries are a fundamental data structure in programming used to map keys to values for efficient lookup and organization. Mastering dictionaries is key to writing optimized Java code. In this comprehensive guide, you‘ll learn all about dictionaries and how to leverage them in your Java programs like a pro! We‘ll cover:

7. www.codeease.net › programming › javadictionary in java | Code Ease

   www.codeease.net › programming › java

   • Cached

   Dec 30, 2023 · In Java, a dictionary is often implemented using the HashMap class from the java.util package. A HashMap is a collection that stores key-value pairs, where each key must be unique. Here's a descriptive example of using a dictionary in Java with the HashMap class: java.

8. People also ask

   Can a dictionary be used in Java?

   • Certainly! In Java, a dictionary is often implemented using the HashMap class from the java.util package. A HashMap is a collection that stores key-value pairs, where each key must be unique. Here's a descriptive example of using a dictionary in Java with the HashMap class:

   dictionary in java | Code Ease

   www.codeease.net/programming/java/dictionary-in-java

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   What is a dictionary class in Java?

   • The Dictionary class is an abstract class and cannot be instantiated directly. Instead, it provides the basic operations for accessing the key-value pairs stored in the collection, which are implemented by its concrete subclass java.util.Hashtable.

   Java.util.Dictionary Class in Java - GeeksforGeeks

   www.geeksforgeeks.org/java-util-dictionary-class-java/

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   What are dictionaries in Java?

   • Keys and values can be any Java object. Common implementations are HashMap and Hashtable. Not thread-safe by default. Dictionaries go by other names like maps, hashmaps or associative arrays in other languages. But the key concept remains – pair data using keys for easy access. Here are some common use cases for dictionaries in Java:

   The Complete Guide to Effectively Using Dictionaries in Java

   thelinuxcode.com/create-a-dictionary-in-java/

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   What is a dictionary class?

   • The Dictionary class is the abstract parent of any class, such as Hashtable, which maps keys to values. Every key and every value is an object. In any one Dictionary object, every key is associated with at most one value. Given a Dictionary and a key, the associated element can be looked up.

   Dictionary (Java Platform SE 8 ) - Oracle

   docs.oracle.com/javase/8/docs//api/java/util/Dictionary.html

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9. javatothepoint.com › dictionary-class-in-javaDictionary Class in Java - Java To The Point

   javatothepoint.com › dictionary-class-in-java

   • Cached

   May 10, 2023 · The Java API provides the Dictionary class to implement a dictionary. The Dictionary class is an abstract class that defines a data structure for managing key-value pairs. It is the superclass of the Hashtable and Properties classes.