This is a bug in javac starting from JDK 9 (which made some changes with regard to string concatenation, which I suspect is part of the problem), as confirmed by the javac team under the bug id JDK-8204322. If you look at the corresponding bytecode for the line: array[i++%size] += i + ” “; It … Read more
Both map and flatMap can be applied to a Stream<T> and they both return a Stream<R>. The difference is that the map operation produces one output value for each input value, whereas the flatMap operation produces an arbitrary number (zero or more) values for each input value. This is reflected in the arguments to each … Read more
Go to File > Settings > Build, Execution, Deployment > Compiler > Java Compiler If on a Mac, it’s under Intellij IDEA > Preferences… > Build, Execution, Deployment > Java Compiler Change Target bytecode version to 1.8 of the module that you are working for. If you are using Maven Add the compiler plugin to … Read more
The easiest method is to use the toArray(IntFunction<A[]> generator) method with an array constructor reference. This is suggested in the API documentation for the method. String[] stringArray = stringStream.toArray(String[]::new); What it does is find a method that takes in an integer (the size) as argument, and returns a String[], which is exactly what (one of … Read more
Based on Collectors documentation it’s as simple as: Map<String, Choice> result = choices.stream().collect(Collectors.toMap(Choice::getName, Function.identity()));
Usually, one would call the reduce method using Math.max(int, int) as follows: reduce(new IntBinaryOperator() { int applyAsInt(int left, int right) { return Math.max(left, right); } }); That requires a lot of syntax for just calling Math.max. That’s where lambda expressions come into play. Since Java 8 it is allowed to do the same thing in … Read more
Oracle has a poor record for making it easy to install and configure Java, but using Homebrew, the latest OpenJDK (Java 14) can be installed with: brew install –cask adoptopenjdk8 For the many use cases depending on an older version (commonly Java 8), the AdoptOpenJDK project makes it possible with an extra step. brew tap … Read more