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Java

HttpClient Java Get Example with Query String and Custom Headers

Apache HttpClient java library is my most preferred HttpClient library for making HTTP requests. One can easily add parameters, body, and custom headers with clean interfaces. Since version 4.0 it also provides EntityUtils to read the response from HttpResponse into string and byte arrays. Here is a complete example to make get requests with parameres […]

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Java

Quickest way to append text to a file in Java

In Java, there are several different ways to append text in a file. For file operations, Java provides several classes. To appending text quickly you can use Files class. Append text to file example: try { Files.write(Paths.get(“file1.txt”), “text to append”.getBytes(), StandardOpenOption.APPEND); } catch (IOException e) { // To exception handling here } But above method […]

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Java

How does Java for-each loop works?

Loops in programming languages used to iterate over collections like for loop, while .. do etc. In Java iterating over collections looks very ugly. Consider method in the following example which uses for loop to iterate over a collection. public static void main(String[] args) { List fruitList = new ArrayList(); fruitList.add(“mango”); fruitList.add(“banana”); fruitList.add(“apple”); printFruits(fruitList); } […]

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Java

Apache HttpClient with CookieStore (cookie support) in Java

In java many time we need to make a request with cookies support. For example, if a REST service is configured to manage session using cookie session or cookie-based session key then we need to use HTTP client with cookie support. For this Apache HttpClient client provides HttpClientBuilder Class, CookieStore interface and BasicCookieStore. Using these […]

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Java

Manually Closing connection of Apache HttpClient in Java

While Using Apache HttpClient library to make Http requests, we should always release connection immediately after completion of the operation. For making HttpRequest Apache HttpClient library provides CloseableHttpClient and CloseableHttpResponse classes which implements java closable interface. By calling the close method of a closeable object in finally block we can close or dispose of connection […]

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Java

Apache HttpClient Response Hadling in Java

Apache HttpClient library provides the ResponseHandler interface. By implementing ResponseHandler you can handle HTTP responses in a clean way. Using the response handler is the recommended way of executing HTTP requests and processing HTTP responses. This approach of handling response enables the caller to concentrate on the process of digesting HTTP responses and to delegate […]

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Java

Best way to round number to nth decimal place in Java

To format numbers, Java provides classes like NumberFormat and DecimalFormat classes. DecimalFormat is a concrete subclass of NumberFormat that formats decimal numbers. It has a variety of features designed to make it possible to parse and format numbers in any locale. All of these can be localized. Read more about DecimalFormat class on Oracle website. […]

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Java

What are ways to split the string in Java?

Java String class provides a method to split the string using a delimiter. It takes delimiter as a regular expression and Splits this string around matches of the given regular expression. This method has two overloaded versions. public String[] split(String regex, int limit) The array returned by this method contains each substring of this string that […]

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Java

Best way to generate random integers within a specific range in Java

There are many classes in Java to generate random numbers. Random and ThreadLocalRandom are best to generate numbers between ranges. ThreadLocalRandom class Since Java 7, it provides ThreadLocalRandom class to generate random numbers. A random number generator isolated to the current thread. Like the global Random generator used by the Math class, a ThreadLocalRandom is […]

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Java

Best and Simplest ways to print Java Array

Many time printing arrays in Java are required to logging and debugging purpose. In Java provides Arrays.toString(arr) or Arrays.deepToString(arr) for arrays within arrays (a nested array) to formatting simple arrays into printable strings. Example of printing a simple array: String names[] = new String[] {“ssp”,”anu”,”kirti”,”shaurya”}; System.out.println(names); System.out.println(Arrays.toString(names)); the output of above code is given below: [Ljava.lang.String;@2a139a55 [ssp, anu, […]