Why does List.remove(int) throw java.lang.UnsupportedOperationException? [duplicate]
You’re using it on a List implementation returned by Arrays.asList(), which returns a fixed-length collection, therefore a remove is unsupported.
java
TestNG by default disables loading DTD from unsecure Urls
Yes, that’s the default behavior of TestNG and I had introduced it through that pull request to fix the bug https://github.com/cbeust/testng/issues/2022 To set the JVM arguments in intelliJ, choose Run > Edit Configurations, and add this JVM argument in the VM options section after -ea (which would be there by default. For more information on … Read more
How to add features missing from the Java regex implementation?
From your edited example, I can now see what you would like. And you have my sympathies in this, too. Java’s regexes are a long, long, long ways from the convenience you find in Ruby or Perl. And they pretty much always will be; this cannot be fixed, so we’re stuck with this mess forever … Read more
Displaying the last two digits of the current year in Java
You can simply use the modulo operator: int lastTwoDigits = Calendar.getInstance().get(Calendar.YEAR) % 100; Edit: Using a SimpleDateFormat, as @R.J proposed, is the better solution if you want the result to be a string. If you need an integer, use modulo.
Java: Sort an unmodifiable list
List unmodifiableList = Collections.unmodifiableList(list); List newList = new ArrayList(unmodifiableList); Collections.sort(newList); The constructor of ArrayList takes an existing list, reads its elements (without modifying them!), and adds them to the new List.
ModelMapper, mapping list of Entites to List of DTO objects
You can create util class: public class ObjectMapperUtils { private static final ModelMapper modelMapper; /** * Model mapper property setting are specified in the following block. * Default property matching strategy is set to Strict see {@link MatchingStrategies} * Custom mappings are added using {@link ModelMapper#addMappings(PropertyMap)} */ static { modelMapper = new ModelMapper(); modelMapper.getConfiguration().setMatchingStrategy(MatchingStrategies.STRICT); } … Read more
Does Java have an “is kind of class” test method
if(object instanceof WhereStatement) { WhereStatement where = (WhereStatement) object; doSomething(where); } Note that code like this usually means that your base class is missing a polymorphic method. i.e. doSomething() should be a method of Statement, possibly abstract, that is overridden by sub-classes.
Java ArrayList Index
You have ArrayList all wrong, You can’t have an integer array and assign a string value. You cannot do a add() method in an array Rather do this: List<String> alist = new ArrayList<String>(); alist.add(“apple”); alist.add(“banana”); alist.add(“orange”); String value = alist.get(1); //returns the 2nd item from list, in this case “banana” Indexing is counted from 0 … Read more
Worst Java practice found in your experience? [closed]
I had to maintain java code, where most of the Exception handling was like: catch( Exception e ) {}