diff --git a/src/main/java/controller/LadderGameController.java b/src/main/java/controller/LadderGameController.java
index 5be2a3df..9deb0c50 100644
--- a/src/main/java/controller/LadderGameController.java
+++ b/src/main/java/controller/LadderGameController.java
@@ -1,6 +1,5 @@
 package controller;
 
-import domain.CountOfLine;
 import domain.Height;
 import domain.Ladder;
 import domain.RungsBuilder;
diff --git a/src/main/java/domain/CountOfLine.java b/src/main/java/domain/CountOfLine.java
index 9ea18dd2..c0fd1d0d 100644
--- a/src/main/java/domain/CountOfLine.java
+++ b/src/main/java/domain/CountOfLine.java
@@ -1,9 +1,12 @@
 package domain;
 
+import java.util.function.Predicate;
 import util.Errors;
 
 public record CountOfLine(int value) {
 
+    private static final Predicate<Integer> ismpty = value -> value <= 0;
+
     public CountOfLine {
         validate(value);
     }
@@ -13,7 +16,7 @@ private void validate(int value) {
     }
 
     private void validateIsNotEmpty(int value) {
-        if (value <= 0) {
+        if (ismpty.test(value)) {
             throw new IllegalArgumentException(Errors.LADDERS_MUST_CONTAINS_LEAST_ONE_LADDER);
         }
     }
diff --git a/src/main/java/domain/Height.java b/src/main/java/domain/Height.java
index f6408d6d..84be2e89 100644
--- a/src/main/java/domain/Height.java
+++ b/src/main/java/domain/Height.java
@@ -1,9 +1,12 @@
 package domain;
 
+import java.util.function.Predicate;
 import util.Errors;
 
 public record Height(int value) {
 
+    private static final Predicate<Integer> isNegative = value -> value <= 0;
+
     public Height {
         validate(value);
     }
@@ -13,7 +16,7 @@ private void validate(int value) {
     }
 
     private void validatePositive(int value) {
-        if (value <= 0) {
+        if (isNegative.test(value)) {
             throw new IllegalArgumentException(Errors.LADDER_HEIGHT_MUST_BE_POSITIVE);
         }
     }
diff --git a/src/main/java/domain/Ladder.java b/src/main/java/domain/Ladder.java
index 6488a9d9..0ec013cf 100644
--- a/src/main/java/domain/Ladder.java
+++ b/src/main/java/domain/Ladder.java
@@ -32,11 +32,8 @@ private void validateLaddersHeight(List<Line> lines) {
     }
 
     private void validatePointStatus(List<Line> lines) {
-        for (int index = 0; index < lines.size() - 1; index++) {
-            Line nowLine = lines.get(index);
-            Line nextLine = lines.get(index + 1);
-            validateRungInSamePosition(nowLine, nextLine);
-        }
+        IntStream.range(0, lines.size() - 1)
+            .forEach(index -> validateRungInSamePosition(lines.get(index), lines.get(index + 1)));
     }
 
     private void validateRungInSamePosition(Line nowLine, Line nextLine) {
@@ -46,8 +43,7 @@ private void validateRungInSamePosition(Line nowLine, Line nextLine) {
     }
 
     private boolean isRungInSamePosition(Line nowLine, Line nextLine) {
-         int maxPosition = nowLine.getHeight();
-        return IntStream.range(0, maxPosition)
+        return IntStream.range(0, nowLine.getHeight())
             .allMatch(
                 position -> nowLine.isConnectedToRightLineAt(position) == nextLine.isConnectedToLeftLineAt(position));
     }
@@ -68,8 +64,8 @@ public Map<String, String> getResult() {
 
         for (int nowIndex = 0; nowIndex < lines.size(); nowIndex++) {
             int finalIndex = calculateTargetIndex(nowIndex, height);
-             String name = getNameOfLine(nowIndex);
-             String outcome = getOutcomeOfLine(finalIndex);
+            String name = getNameOfLine(nowIndex);
+            String outcome = getOutcomeOfLine(finalIndex);
             result.put(name, outcome);
         }
         return result;
diff --git a/src/main/java/domain/Line.java b/src/main/java/domain/Line.java
index d9e23db3..d31f0a79 100644
--- a/src/main/java/domain/Line.java
+++ b/src/main/java/domain/Line.java
@@ -1,7 +1,8 @@
 package domain;
 
-import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
 import util.Errors;
 
 public class Line {
@@ -17,14 +18,13 @@ private Line(Player player, String outcome, List<Point> points) {
         this.points = points;
     }
 
-    public static Line of(Player player, String outcome, List<Boolean> leftRungsStatus, List<Boolean> rightRungsStatus) {
+    public static Line of(Player player, String outcome, List<Boolean> leftRungsStatus,
+                          List<Boolean> rightRungsStatus) {
         validateHeight(leftRungsStatus, rightRungsStatus);
 
-        int maxPosition = leftRungsStatus.size();
-        List<Point> points = new ArrayList<>();
-        for (int position = 0; position < maxPosition; position++) {
-            points.add(new Point(leftRungsStatus.get(position), rightRungsStatus.get(position)));
-        }
+        List<Point> points = IntStream.range(0, leftRungsStatus.size())
+            .mapToObj(position -> new Point(leftRungsStatus.get(position), rightRungsStatus.get(position)))
+            .collect(Collectors.toList());
         return new Line(player, outcome, points);
     }
 
@@ -35,11 +35,9 @@ private static void validateHeight(List<Boolean> leftRungsStatus, List<Boolean>
     }
 
     public List<Boolean> getRightStatus() {
-        List<Boolean> rightStatus = new ArrayList<>();
-        for (Point point : points) {
-            rightStatus.add(point.isConnectedToRightLadder());
-        }
-        return rightStatus;
+        return points.stream()
+            .map(Point::isConnectedToRightLadder)
+            .collect(Collectors.toList());
     }
 
     public int getHeight() {
@@ -55,12 +53,12 @@ public String getOutcome() {
     }
 
     public boolean isConnectedToLeftLineAt(int position) {
-         Point nowPoint = this.points.get(position);
+        Point nowPoint = this.points.get(position);
         return nowPoint.isConnectedToLeftLadder();
     }
 
     public boolean isConnectedToRightLineAt(int position) {
-         Point nowPoint = this.points.get(position);
+        Point nowPoint = this.points.get(position);
         return nowPoint.isConnectedToRightLadder();
     }
 
diff --git a/src/main/java/domain/RandomRungsBuilder.java b/src/main/java/domain/RandomRungsBuilder.java
index 3feb3d83..20472e32 100644
--- a/src/main/java/domain/RandomRungsBuilder.java
+++ b/src/main/java/domain/RandomRungsBuilder.java
@@ -1,6 +1,5 @@
 package domain;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.Random;
 import java.util.stream.Collectors;
@@ -16,12 +15,9 @@ public RandomRungsBuilder() {
 
     @Override
     public List<Boolean> buildAndGetRungsStatus(List<Boolean> prevRungsStatus) {
-        List<Boolean> rungsStatus = new ArrayList<>();
-        for (Boolean doesPrevLadderHaveRung : prevRungsStatus) {
-             boolean nowRungsStatus = generateRungIfAbsent(doesPrevLadderHaveRung);
-            rungsStatus.add(nowRungsStatus);
-        }
-        return rungsStatus;
+        return prevRungsStatus.stream()
+            .map(this::generateRungIfAbsent)
+            .collect(Collectors.toList());
     }
 
     private boolean generateRungIfAbsent(Boolean doesPrevLadderHaveRung) {
diff --git a/src/main/java/service/LadderService.java b/src/main/java/service/LadderService.java
index 3694e342..cc789950 100644
--- a/src/main/java/service/LadderService.java
+++ b/src/main/java/service/LadderService.java
@@ -23,7 +23,7 @@ public LadderService(RungsBuilder rungsBuilder) {
     }
 
     public Ladder createLadder(Height height, List<String> names, List<String> outcomes) {
-        final List<Player> players = getPlayers(names);
+        List<Player> players = getPlayers(names);
         CountOfLine countOfLine = getcountOfLine(players, outcomes);
         List<Line> lineCollection = createLineCollection(countOfLine, height, players, outcomes);
         return new Ladder(lineCollection);