I was working with seemingly simple load job in Redshift. I was generating some data and wanted to store the output in separate table, just to persist it for debugging purposes. However, since the job could be reran if needed, I wanted to…
Recently I was working with the following code:
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import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.stream.Collectors; public class Test { public static void main(String[] args) { List<String> strings = new ArrayList<>(); List<Item> items = strings.stream().map(item -> new Item(new HashMap())).collect(Collectors.toList()); } } class Item { public Map<String, String> metadata; Item(Map<String, String> metadata) { this.metadata = metadata; } } |
I was compiling it with
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java version "1.8.0_221" Java(TM) SE Runtime Environment (build 1.8.0_221-b11) Java HotSpot(TM) 64-Bit Server VM (build 25.221-b11, mixed mode) |
on Windows 10 x64. It wasn’t working because of the following:
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/tmp/java_fR1LWz/Test.java:10: warning: [unchecked] unchecked method invocation: constructor <init> in class Item is applied to given types List<Item> items = strings.stream().map(item -> new Item(new HashMap())).collect(Collectors.toList()); ^ required: Map<String,String> found: HashMap /tmp/java_fR1LWz/Test.java:10: warning: [unchecked] unchecked conversion List<Item> items = strings.stream().map(item -> new Item(new HashMap())).collect(Collectors.toList()); ^ required: Map<String,String> found: HashMap /tmp/java_fR1LWz/Test.java:10: warning: [unchecked] unchecked method invocation: method map in interface Stream is applied to given types List<Item> items = strings.stream().map(item -> new Item(new HashMap())).collect(Collectors.toList()); ^ required: Function<? super T,? extends R> found: Function<String,Item> where T,R are type-variables: T extends Object declared in interface Stream R extends Object declared in method <R>map(Function<? super T,? extends R>) /tmp/java_fR1LWz/Test.java:10: warning: [unchecked] unchecked call to <R,A>collect(Collector<? super T,A,R>) as a member of the raw type Stream List<Item> items = strings.stream().map(item -> new Item(new HashMap())).collect(Collectors.toList()); ^ where R,A,T are type-variables: R extends Object declared in method <R,A>collect(Collector<? super T,A,R>) A extends Object declared in method <R,A>collect(Collector<? super T,A,R>) T extends Object declared in interface Stream /tmp/java_fR1LWz/Test.java:10: error: incompatible types: Object cannot be converted to List<Item> List<Item> items = strings.stream().map(item -> new Item(new HashMap())).collect(Collectors.toList()); ^ 1 error 4 warnings |
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sudo yum update -y --releasever=latest --cve CVE-2019-0232 sudo shutdown -r now |
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