This might be a dumb question but what is the simplest way to read and parse JSON from URL in Java? In Groovy, it’s a matter of few lines of code. Java examples that I find are ridiculously long (and have huge exception handling block). All I want to do is to read the content … Read more
Finally, I modified the sort function in this manner to get sorted data.
I am on JDK 8u25 on Windows 8, and I am experiencing a problem with my Java installation. I can run javac perfectly fine, but running java produces this error message: How do I fix this? I think the problem has to do with my environment variables. The important variables, as I have set them, … Read more
To answer your question about the while loop condition directly (are the two conditions equivalent?): No, they aren’t equivalent, but it’s only a small change needed. The following two conditions are equivalent by DeMorgan’s Law. So basically you have to add a ! before your second while loop condition to make them equivalent (assuming it really was a … Read more
Eclipse can’t work out what you want to run and since you’ve not run anything before, it can’t try re-running that either. Instead of clicking the green ‘run’ button, click the dropdown next to it and chose Run Configurations. On the Android tab, make sure it’s set to your project. In the Target tab, set … Read more
Double.MAX_VALUE is the maximum value a double can represent (somewhere around 1.7*10^308). This should end in some calculation problems, if you try to subtract the maximum possible value of a data type. Even though when you are dealing with money you should never use floating point values especially while rounding this can cause problems (you will … Read more
Alright, let’s elaborate with some simplified explanation about the Scanner class. It is a standard Oracle class which you can use by calling the import java.util.Scanner. So let’s make a basic example of the class: Now when you call Scanner input = new Scanner(System.in); you make a new object of the Scanner class (so you make a new “Scanner”) and you store … Read more
Everything in a Java program not explicitly set to something by the programmer, is initialized to a zero value. For references (anything that holds an object) that is null. For int/short/byte/long that is a 0. For float/double that is a 0.0 For booleans that is a false. For char that is the null character ‘\u0000’ (whose decimal equivalent is 0). When … Read more
The HTTP 502 “Bad Gateway” response is generated when Apache web server does not receive a valid HTTP response from the upstream server, which in this case is your Tomcat web application. Some reasons why this might happen: Tomcat may have crashed The web application did not respond in time and the request from Apache … Read more
In terms of Java, both the class HashMap and the class Dictionary are implementations of the “Map” abstract data type. Abstract data types are not specific to any one programming language, and the Map ADT can also be known as a Hash, or a Dictionary, or an Associative Array (others at http://en.wikipedia.org/wiki/Associative_array). (Notice we’re making a distinction between the Dictionary class and the Dictionary … Read more