java

[Solved] Here is a simple java code giving an error may i know why so

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Consider this line, Test1 t2 = t1.print();//wrong code You have to explicitly typecast in this situation. Test1 t2 = (Test1)t1.print();//correct code You have to explicitly typecast in case of narrowing conversion(Parent class—>child class) Your compiler automatically typecasts in widening conversions(Child class—>Parent class). 3 solved Here is a simple java code giving an error may i … Read more

[Solved] Need the words between the ” – ” ONLY string splitting [duplicate]

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So basically you to first split by – and then each side by a non-word character. Therefore you can try: String s = “ABC_DEF-HIJ (KL MNOP_QRS)”; String[] splits = s.split(“-“); // {“ABC_DEF”, “HIJ (KL MNOP_QRS)”} String[] lefts = split[0].split(“[^a-zA-Z]”); // {“ABC”, “DEF”} String[] rights = split[1].split(“[^a-zA-Z]”); // {“HIJ”, “”, “KL”, “MNOP”, “QRS”} String string1 = … Read more

[Solved] Static class instance inside class

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What you have there is a static method getLibrary() that returns the same instance for all callers. That’s called a Singleton – although there’s better ways to code them. Then again your supposed Singleton (TestLibrary) exhibits methods that when called change internal state – most important, the ErrorHandler. This will cause strange behaviour, especially in … Read more

[Solved] Operations on Strings

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If two strings are equal to each other. When comparing two strings, you have to pass in the strings. public static boolean isEquals(String a, String b) { if (a.length() != b.length()) return false; return isEquals(a, b, 0); } private static boolean isEquals(String a, String b, int index) { if (index >= a.length()) return true; if … Read more

[Solved] Got a very strange syntax error in java

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With the commented-out code uncommented, you’re trying to declare a constructor directly within a method. You can’t do that in Java. // You can’t do this buttonPlay.addListener(new ClickListener(){ // 1 public void clicked(InputEvent event, float x, float y) { // 2 public GameScreen(Create create) { // 3 this.create = create; // 3 } // 3 … Read more

[Solved] How “java.util.Comparator.compare(String o1, String o2) ” method works

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Strings are comparable in a lexicographic order (i.e., the order they’d appear in a dictionary). If you want to implement a Comparator for clothes sizes, you’d have to write the logic yourself. E.g.: public class ClothesSizeComparator implements Comparator<String> { private static final List<String> SIZES = Arrays.asList(“XS”, “S”, “M”, “L”, “XL”, “XXL”, “3XL”); @Override public int … Read more

[Solved] How to make ArrayList of hashset in java? [closed]

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Just make an ArrayList of HashSets : ArrayList<HashSet<Integer>> list = new ArrayList<HashSet<Integer>>(); Then create HashSets, fill them, and put them in your ArrayList normally. HashSet<Integer> set = new HashSet<Integer>(); set.add(1); set.add(whateverIntValue); list.add(set); You can then get the nth HashSet of your list using list.get(n). solved How to make ArrayList of hashset in java? [closed]

[Solved] How can I tell if a method is being called?

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You can use a private instance variable counter, that you can increment on every call to your method: – public class Demo { private int counter = 0; public void counter() { ++counter; } } Update : – According to your edit, you would need a static variable, which is shared among instances. So, once … Read more

[Solved] Why IF condition is not fulfilled on android [duplicate]

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It shouldn’t continue, it should throw a NullPointerException that you may intercept in the catch block. When you try if (!spnOptionSelectedTypes.equals(null)) it should throw this exception because spnOptionSelectedTypes is null so it is not a String and does not have any equals() method. Edit: It allows the first if to pass because it has 2 … Read more

[Solved] Spring Boot external properties not loaded

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If you do new Admin (), you are creating a new instance of Admin and not a spring bean. So you don’t get any advantages which spring provides(for example Dependency Injection) And hence the value is null. Instead you should Autowire it in your class. This way spring will inject the instance of Admin that … Read more