StreamToLoop inspection: simplify toMap mergers (a,b)->a (use putIfAbsent) and (a,b)->b (use put)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterToMapPut.java

@@ -0,0 +1,21 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class Main {
+  public static TreeMap<Integer, String> test(List<String> strings) {
+      TreeMap<Integer, String> map = new TreeMap<>();
+      for (String s1 : strings) {
+          if (!s1.isEmpty()) {
+              map.put(s1.length(), s1.trim());
+          }
+      }
+      return map;
+  }
+
+  public static void main(String[] args) {
+    System.out.println(test(Arrays.asList()));
+    System.out.println(test(Arrays.asList("a", "bbb", "cc", "d", "eee", "")));
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterToMapSupplier.java

@@ -8,7 +8,7 @@ public class Main {
       TreeMap<Integer, String> map = new TreeMap<>();
       for (String s1 : strings) {
           if (!s1.isEmpty()) {
-              map.merge(s1.length(), s1, (s, string) -> s);
+              map.putIfAbsent(s1.length(), s1);
           }
       }
       return map;

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/beforeToMapPut.java

@@ -0,0 +1,16 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class Main {
+  public static TreeMap<Integer, String> test(List<String> strings) {
+    return strings.stream().filter(s -> !s.isEmpty())
+      .col<caret>lect(Collectors.toMap(String::length, String::trim, (s, string) -> string, TreeMap::new));
+  }
+
+  public static void main(String[] args) {
+    System.out.println(test(Arrays.asList()));
+    System.out.println(test(Arrays.asList("a", "bbb", "cc", "d", "eee", "")));
+  }
+}