Java - Lambda expressions Target typing

By -

Target typing

Lambda expressions don’t have type information. The actual type of a lambda expression is deduced by compiler from its surrounding context at compile time.

For example, lambda expression () -> System.out.println("Hello World!") can appear in any context where requires an instance of functional interface with the only abstract method takes no arguments and returns void. This could be java.lang.Runnable interface or any other functional interfaces created by third-party libraries or application code. So the same lambda expression can have different types in different contexts. Expressions like lambda expressions which have deduced type influenced by target type are called poly expressions.


Standalone expressions and Poly expressions 
Standalone expressions are expressions which have type that can be determined from the contents of expressions themselves. For example, a + b and str.substring(1) are standalone expressions. Poly expressions are expressions which have type that can be influenced by target type. Lambda expressions and method references are always poly expressions. Some other expressions may be poly expressions in certain cases.

Comments

Post a Comment

Popular posts from this blog

Today Walkin 14th-Sept

By -
Image
14th Sept 2017 ( GO Through all List) Read Walkin details properly , Try to call company before attending if possible !!! ==================================== 1. Myntra through fresherworld (Call Based , Venue shared to shortlisted candidates) _____________________________ 2. Magna : Hiring for Client Harman : C++
Read more

Hibernate Search - Elasticsearch with JSON manipulation

By -
Elasticsearch with JSON manipulation Elasticsearch ships with many features. It is possible that at some point, one feature you need will not be exposed by the Search DSL. To work around such limitations, Hibernate Search provides ways to: Transform the HTTP request sent to Elasticsearch for search queries. Read the raw JSON of the HTTP response received from Elasticsearch for search queries. Direct changes to the HTTP request may conflict with Hibernate Search features and be supported differently by different versions of Elasticsearch. Similarly, the content of the HTTP response may change depending on the version of Elasticsearch, depending on which Hibernate Search features are used, and even depending on how Hibernate Search features are implemented. Thus, features relying on direct access to HTTP requests or responses cannot be guaranteed to continue to work when upgrading Hibernate Search, even for micro upgrades (x.y.z to x.y.(z+1)). Use this at your own risk.
Read more

Spring Elasticsearch Operations

By -
Elasticsearch Operations Spring Data Elasticsearch uses two interfaces to define the operations that can be called against an Elasticsearch index. These are ElasticsearchOperations and ReactiveElasticsearchOperations. Whereas the first is used with the classic synchronous implementations, the second one uses reactive infrastructure. The default implementations of the interfaces offer: Read/Write mapping support for domain types. A rich query and criteria api. Resource management and Exception translation. ElasticsearchTemplate The ElasticsearchTemplate is an implementation of the ElasticsearchOperations interface using the Transport Client. @Configuration public class TransportClientConfig extends ElasticsearchConfigurationSupport {   @Bean   public Client elasticsearchClient() throws UnknownHostException {                      Settings settings = Settings.builder().put("cluster.name", "elasticsearch").build();     TransportClient client = new P
Read more