You can use the List.addAll() method. It accepts a Collection as an argument, and your set is a Collection. List<String> mainList = new ArrayList<String>(); mainList.addAll(set); EDIT: as respond to the edit of the question. It is easy to see that if you want to have a Map with Lists as values, in order to have … Read more
Try: import android.os.Vibrator; … Vibrator v = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE); // Vibrate for 500 milliseconds if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) { v.vibrate(VibrationEffect.createOneShot(500, VibrationEffect.DEFAULT_AMPLITUDE)); } else { //deprecated in API 26 v.vibrate(500); } Note: Don’t forget to include permission in AndroidManifest.xml file: <uses-permission android:name=”android.permission.VIBRATE”/>
You should always use enums when a variable (especially a method parameter) can only take one out of a small set of possible values. Examples would be things like type constants (contract status: “permanent”, “temp”, “apprentice”), or flags (“execute now”, “defer execution”). If you use enums instead of integers (or String codes), you increase compile-time … Read more
Oh, those coding styles are to be taken with a bit of salt. (+) Passing an Optional result to another method, without any semantic analysis; leaving that to the method, is quite alright. (-) Using Optional parameters causing conditional logic inside the methods is literally contra-productive. (-) Needing to pack an argument in an Optional, … Read more
If the idea is to print integers stored as doubles as if they are integers, and otherwise print the doubles with the minimum necessary precision: public static String fmt(double d) { if(d == (long) d) return String.format(“%d”,(long)d); else return String.format(“%s”,d); } Produces: 232 0.18 1237875192 4.58 0 1.2345 And does not rely on string manipulation.
No, you can’t do this in Java. Aside from anything else, d would then presumably be an instance of A (given the normal idea of “extends”), but users who only knew about A wouldn’t know about it – which defeats the point of an enum being a well-known set of values. If you could tell … Read more
Short answer: Date in = new Date(); LocalDateTime ldt = LocalDateTime.ofInstant(in.toInstant(), ZoneId.systemDefault()); Date out = Date.from(ldt.atZone(ZoneId.systemDefault()).toInstant()); Explanation: (based on this question about LocalDate) 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 … Read more
The object your method decompressGZIP() needs is a byte[]. So the basic, technical answer to the question you have asked is: byte[] b = string.getBytes(); byte[] b = string.getBytes(Charset.forName(“UTF-8”)); byte[] b = string.getBytes(StandardCharsets.UTF_8); // Java 7+ only However the problem you appear to be wrestling with is that this doesn’t display very well. Calling toString() … Read more
With the Java optional package or Oracle JDK installed, adding one of the following lines to your ~/.bash_profile file will set the environment variable accordingly. export JAVA_HOME=”$(/usr/libexec/java_home -v 1.6)” or export JAVA_HOME=”$(/usr/libexec/java_home -v 1.7)” or export JAVA_HOME=”$(/usr/libexec/java_home -v 1.8)” or simply export JAVA_HOME=”$(/usr/libexec/java_home)” Note: If you installed openjdk on mac using brew, run sudo ln … Read more
This bizarre message means that the trustStore you specified was: empty, not found, or couldn’t be opened (due to wrong/missing trustStorePassword, or file access permissions, for example). See also @AdamPlumb’s answer below.