Fail Fast vs Fail Safe in Java

A system is called fail-fast if it stops immediately its execution when an error occurred. The system does not continue with the errors and these errors in the fail fast systems are immediately exposed. But, fail-safe system does the opposite thing. The fail-safe system does not stop its execution despite an error or a fault is occurred in the system. The system continues with the operations hiding the errors instead of exposing the errors immediately. The only difference is fail safe iterator doesn’t throw any Exception but fail-fast Iterator. A…

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TreeSet in Java

What is TreeSet A NavigableSet implementation based on a TreeMap. The elements are ordered using their natural ordering, or by a Comparator provided at set creation time, depending on which constructor is used. Like HashSet, TreeSet also implements Set interface. Like HashSet, TreeSet allows to store only unique elements in their objects. HashSet is much faster than TreeSet because HashSet has constant-time, whereas TreeSet has log-time for most operations like add, remove and contains. Unlike HashSet, TreeSet offers a few handy methods to deal with the ordered set like first(),…

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Spring NamedParameterJdbcTemplate and Collections.singletonMap Example

Introduction In this post I will show you how to use NamedParameterJdbcTemplate and Collections.singletonMap to execute query for returning result. The NamedParameterJdbcTemplate class adds support for programming JDBC statements using named parameters, as opposed to programming JDBC statements using only classic placeholder (?) arguments. The NamedParameterJdbcTemplate class wraps a JdbcTemplate, and delegates to the wrapped JdbcTemplate to do much of its work. An SqlParameterSource is a source of named parameter values to a NamedParameterJdbcTemplate. The Collections.singletonMap returns an immutable map, mapping only the specified key to the specified value. The…

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Collection merging in Spring

With this example we will show you how to merge Collections in Spring. Since Spring 2.0, the container supports merging of collections. You can define <prop/>, <list/>, <map/> and <set/> of parent-style and then you can inherit the child-style element and override values of each type from parent collections. That is, the child collection’s values are the result of merging the elements of the parent and child collections, with the child’s collection elements overriding values specified in the parent collection. If you already have an idea on how to create…

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Working with Collection Element Type Map in Spring Application

With this example I will show you how to inject Collection Type Map in Spring Bean. I am going to show you in Spring Boot framework how to read map based key/value pair. I will also show you how to read the map based values from traditional XML config file. In order to show how Collections can be injected in a Spring Bean I will create a simple Spring Bean with a property Map. For example, the map of elements are changeable over time or your application needs to update…

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Collection Element List in Spring

With this example I will show you how to inject List Collection in Spring application. The collection type I am going to show you is List or Array. I am going to use Spring Boot framework. I will show you various ways of loading a list of configurable properties in Spring application. The list of elements you use generally coming from some persistent storage or external services but you may need to configure a list of elements in the properties files for some situations. For example, the list of elements…

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Working with Collection Element Props in Spring Application

With this example I will show you how to inject Collections type Props in Spring applications. This is similar to the element type Map I had shown in another example. I am going to use Spring Boot framework but I will show you both using application.properties file as well as traditional XML config file to configure the props elements. In order to show how Collections type Props can be injected in a Spring Bean I will create a simple Spring Bean with a property Properties.

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