First, and most important – all Spring beans are managed – they “live” inside a container, called “application context”. Second, each application has an entry point to that context. Web applications have a Servlet, JSF uses a el-resolver, etc. Also, there is a place where the application context is bootstrapped and all beans – autowired. … Read more
I know I’m a bit late for that one, but I’ll share what I did too, in case it helps someone else : HashMap<String, HashMap> selects = new HashMap<String, HashMap>(); for(Map.Entry<String, HashMap> entry : selects.entrySet()) { String key = entry.getKey(); HashMap value = entry.getValue(); // do what you have to do here // In your … Read more
Here’s an utility that rounds (instead of truncating) a double to specified number of decimal places. For example: round(200.3456, 2); // returns 200.35 Original version; watch out with this public static double round(double value, int places) { if (places < 0) throw new IllegalArgumentException(); long factor = (long) Math.pow(10, places); value = value * factor; … Read more
As others mentioned, it’s only possible via reflection in certain circumstances. If you really need the type, this is the usual (type-safe) workaround pattern: public class GenericClass<T> { private final Class<T> type; public GenericClass(Class<T> type) { this.type = type; } public Class<T> getMyType() { return this.type; } }
One rule-of-thumb: ask yourself “Does it make sense to call this method, even if no object has been constructed yet?” If so, it should definitely be static. So in a class Car you might have a method: double convertMpgToKpl(double mpg) …which would be static, because one might want to know what 35mpg converts to, even … Read more
Short answer Date input = new Date(); LocalDate date = input.toInstant().atZone(ZoneId.systemDefault()).toLocalDate(); Explanation Despite its name, java.util.Date represents an instant on the time-line, not a “date”. The actual data stored within the object is a long count of milliseconds since 1970-01-01T00:00Z (midnight at the start of 1970 GMT/UTC). The equivalent class to java.util.Date in JSR-310 is … Read more
Something in the lines of myString.split(“\\s+”); This groups all white spaces as a delimiter. So if I have the string: “Hello[space character][tab character]World” This should yield the strings “Hello” and “World” and omit the empty space between the [space] and the [tab]. As VonC pointed out, the backslash should be escaped, because Java would first … Read more
Java 7 now has a System.lineSeparator() method.
One way is to create a Spliterator from the Iterator and use that as a basis for your stream: Iterator<String> sourceIterator = Arrays.asList(“A”, “B”, “C”).iterator(); Stream<String> targetStream = StreamSupport.stream( Spliterators.spliteratorUnknownSize(sourceIterator, Spliterator.ORDERED), false); An alternative which is maybe more readable is to use an Iterable – and creating an Iterable from an Iterator is very easy … Read more
replace will replace all instances of a letter. All you need to do is use substring(): public String method(String str) { if (str != null && str.length() > 0 && str.charAt(str.length() – 1) == ‘x’) { str = str.substring(0, str.length() – 1); } return str; }