java-8

问题 I would like to analyse .class files and get information about which class uses which other class. jdeps is a command line tool which allows you to display some information in the console, but I would like to avoid calling an external tool and scraping the command line output. 回答1: All dependencies are recorded at a central place of a class file, the constant pool. So to efficiently process all dependencies, you need a library allowing to process the constant pool without looking at the rest

问题 Forgive me if the solution is very obvious but I can't seem to figure out how to do this public static void main(String[] args) { Map<String, String> map = new HashMap<>(); map.put("b1", "a1"); map.put("b2", "a2"); map.put("b3", "a1"); Map<String, List<String>> mm = map.values().stream().collect(Collectors.groupingBy(m -> m)); System.out.println(mm); } I want to group by based on values in hashmap. I want the output to be {a1=[b1, b3], a2=[b2]} but it is currently coming as {a1=[a1, a1], a2=

问题 Forgive me if the solution is very obvious but I can't seem to figure out how to do this public static void main(String[] args) { Map<String, String> map = new HashMap<>(); map.put("b1", "a1"); map.put("b2", "a2"); map.put("b3", "a1"); Map<String, List<String>> mm = map.values().stream().collect(Collectors.groupingBy(m -> m)); System.out.println(mm); } I want to group by based on values in hashmap. I want the output to be {a1=[b1, b3], a2=[b2]} but it is currently coming as {a1=[a1, a1], a2=

问题 I have a class Sales. Class Sales { String month; String year; String city; String state; String sales; } Have a list of Sales objects "result" :[ { "month" : "JAN", "year": "2000", "state" : "State1", "city" : "City1", "sales" : "10" }, { "month" : "JAN", "year" : "2000", "state" : "State1", "city" : "City2", "sales" : "20" }, { "month" : "JAN", "year" : "2000", "state" : "State2", "city" : "City3", "sales" : "30", }, { "month" : "JAN", "year" : "2000", "state" : "State2", "city" : "City1",

问题 I have a class Sales. Class Sales { String month; String year; String city; String state; String sales; } Have a list of Sales objects "result" :[ { "month" : "JAN", "year": "2000", "state" : "State1", "city" : "City1", "sales" : "10" }, { "month" : "JAN", "year" : "2000", "state" : "State1", "city" : "City2", "sales" : "20" }, { "month" : "JAN", "year" : "2000", "state" : "State2", "city" : "City3", "sales" : "30", }, { "month" : "JAN", "year" : "2000", "state" : "State2", "city" : "City1",

问题 I am running a spring boot dockerized application with embedded tomcat. I have a properties file called myconfig.properties under resources folder myconfig.properties myvariable=${ENV_MYVARIABLE} This file content is required during startup of app.The file is consumed by a library which is accessed during startup. Spring boot is replacing the envioronment variables under application.properties file but this env variable in myconfig.properties file is not replaced. The file is no where

问题 I am running a spring boot dockerized application with embedded tomcat. I have a properties file called myconfig.properties under resources folder myconfig.properties myvariable=${ENV_MYVARIABLE} This file content is required during startup of app.The file is consumed by a library which is accessed during startup. Spring boot is replacing the envioronment variables under application.properties file but this env variable in myconfig.properties file is not replaced. The file is no where

问题 I have developed a java application and made it a jar file. I bundled all the dependencies using mvn clean package maven-shaded-plugin. My problem is that although the application works fine in my local machine, it does not work in the server environment. Whenever I run it, I get a NullPointerException which means the variable is not being initialized, which implies the underlying dependency is not working properly. The original question I posted is in here: JMS connection not connecting to

问题 I have a class A in java and interface B in Kotlin. // kotlin interface B { fun optional() } // java class A implements B { } I want to write the default method (Java 8 feature) in Kotlin interface (B) and want to implement it in the class A. How can I achieve it? Thanks in advance. 回答1: In Kotlin, interface methods with bodies are by default compiled as following: // kotlin interface B { fun optional() { println("B optional body") } } is compiled roughly to: public interface B { void

问题 I have two pairs of projects that I develop in NetBeans, both of which have a GUI project, and a library project, where the GUI project depends on the library one. In one of them, NetBeans recognizes that the dependency is local, and indicates as such with an Ma symbol, as seen below, with the dependency project in green: This provides some nice functionality, most notably that the "Navigate to" (ctrl+click) functionality from the GUI project takes me to the source code in the library project