Introduction and feature analysis of Google Collection framework and characteristics

Google Collect is an open source Java library that provides a set of efficient, reliable and easy -to -use collection and concurrent tools for Java developers.The Google Collect framework is based on the Java Collections framework and provides many extensions and enhanced functions on its basis, enabling developers to process collection data and concurrency operations more simply. The characteristics of Google Collect are as follows: 1. Uncharacteristic set: Google Collect provides a series of unchanged collection classes, such as ImmutableList, ImmutableSet, and ImmutableMap.These collection classes are safe threads, and they cannot be modified once they are created.Using uncharacteristic sets can avoid the data consistency brought by concurrent modification, and the non -changing collection is more efficient. The following is an example, showing how to create and use unchanged lists: ImmutableList<String> list = ImmutableList.of("apple", "banana", "orange"); System.out.println (list); // Output [Apple, Banana, Orange] // The following code will throw out UNUPPORTEDOPERATINEXCEPION abnormal list.add("pear"); 2. New collection type: In addition to extending the uncharacteristic set, Google Collect also provides some new collection types, such as Multiset, Multimap, BIMAP, and Table.These collection types can better meet specific business needs. The following is an example of using Multimap: Multimap<String, Integer> multimap = HashMultimap.create(); multimap.put("dog", 1); multimap.put("dog", 2); multimap.put("cat", 3); System.out.println (multimap.get ("dog"); // output [1, 2] 3. Functional programming style: Google Collect supports functional programming styles, providing many functional interfaces and tool classes, such as Function, Predicate, SUPPLIER, and Optional.These interfaces and tools can simplify the collection operation and provide more flexible function programming capabilities. The following is an example of using function: List<Integer> numbers = Lists.newArrayList(1, 2, 3, 4, 5); List<String> squareRoots = numbers.stream() .map(n -> n * n) .map(String::valueOf) .collect(Collectors.toList()); System.out.println (Squareroots); // Output [1, 4, 9, 16, 25] The Google Collect framework also provides many other useful functions and tools, such as cache, concurrent sets, sorters, range sets, etc.It is widely used in various Java projects, providing strong and convenient collection processing capabilities, which greatly improves development efficiency.