diff --git a/HMCL/src/main/java/org/jackhuang/hmcl/ui/FXUtils.java b/HMCL/src/main/java/org/jackhuang/hmcl/ui/FXUtils.java
index 32928e3c7..84133508b 100644
--- a/HMCL/src/main/java/org/jackhuang/hmcl/ui/FXUtils.java
+++ b/HMCL/src/main/java/org/jackhuang/hmcl/ui/FXUtils.java
@@ -318,18 +318,33 @@ public final class FXUtils {
         checkBox.selectedProperty().unbindBidirectional(property);
     }
 
+    /**
+     * Bind combo box selection with given enum property bidirectionally.
+     * You should <b>only and always</b> use {@code bindEnum} as well as {@code unbindEnum} at the same time.
+     * @param comboBox the combo box being bound with {@code property}.
+     * @param property the property being bound with {@code combo box}.
+     * @see #unbindEnum(JFXComboBox)
+     */
+    @SuppressWarnings("unchecked")
     public static void bindEnum(JFXComboBox<?> comboBox, Property<? extends Enum> property) {
         unbindEnum(comboBox);
         ChangeListener<Number> listener = (a, b, newValue) -> {
             ((Property) property).setValue(property.getValue().getClass().getEnumConstants()[newValue.intValue()]);
         };
         comboBox.getSelectionModel().select(property.getValue().ordinal());
-        comboBox.getProperties().put("listener", listener);
+        comboBox.getProperties().put("FXUtils.bindEnum.listener", listener);
         comboBox.getSelectionModel().selectedIndexProperty().addListener(listener);
     }
 
+    /**
+     * Unbind combo box selection with given enum property bidirectionally.
+     * You should <b>only and always</b> use {@code bindEnum} as well as {@code unbindEnum} at the same time.
+     * @param comboBox the combo box being bound with the property which can be inferred by {@code bindEnum}.
+     * @see #bindEnum(JFXComboBox, Property)
+     */
+    @SuppressWarnings("unchecked")
     public static void unbindEnum(JFXComboBox<?> comboBox) {
-        ChangeListener listener = Lang.get(comboBox.getProperties(), "listener", ChangeListener.class).orElse(null);
+        ChangeListener listener = Lang.get(comboBox.getProperties(), "FXUtils.bindEnum.listener", ChangeListener.class).orElse(null);
         if (listener == null) return;
         comboBox.getSelectionModel().selectedIndexProperty().removeListener(listener);
     }
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/game/AssetIndex.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/game/AssetIndex.java
index c5eb0df61..ebade171c 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/game/AssetIndex.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/game/AssetIndex.java
@@ -18,6 +18,7 @@
 package org.jackhuang.hmcl.game;
 
 import com.google.gson.annotations.SerializedName;
+import org.jackhuang.hmcl.util.ToStringBuilder;
 
 import java.util.Collections;
 import java.util.HashMap;
@@ -52,4 +53,8 @@ public final class AssetIndex {
         return Collections.unmodifiableMap(objects);
     }
 
+    @Override
+    public String toString() {
+        return new ToStringBuilder(this).append("virtual", virtual).append("objects", objects).toString();
+    }
 }
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/game/DownloadInfo.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/game/DownloadInfo.java
index 0eddcf612..0ec7b7340 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/game/DownloadInfo.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/game/DownloadInfo.java
@@ -21,6 +21,7 @@ import com.google.gson.JsonParseException;
 import com.google.gson.annotations.SerializedName;
 import org.jackhuang.hmcl.util.Immutable;
 import org.jackhuang.hmcl.util.StringUtils;
+import org.jackhuang.hmcl.util.ToStringBuilder;
 import org.jackhuang.hmcl.util.Validation;
 
 /**
@@ -67,6 +68,11 @@ public class DownloadInfo implements Validation {
         return size;
     }
 
+    @Override
+    public String toString() {
+        return new ToStringBuilder(this).append("url", url).append("sha1", sha1).append("size", size).toString();
+    }
+
     @Override
     public void validate() throws JsonParseException {
         if (StringUtils.isBlank(url))
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/game/ExtractRules.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/game/ExtractRules.java
index 7aa3e7526..a8ed46440 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/game/ExtractRules.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/game/ExtractRules.java
@@ -32,7 +32,7 @@ public final class ExtractRules {
     private final List<String> exclude;
 
     public ExtractRules() {
-        this.exclude = Collections.EMPTY_LIST;
+        this.exclude = Collections.emptyList();
     }
 
     public ExtractRules(List<String> exclude) {
@@ -44,7 +44,7 @@ public final class ExtractRules {
     }
 
     public boolean shouldExtract(String path) {
-        return exclude.stream().noneMatch(it -> path.startsWith(it));
+        return exclude.stream().noneMatch(path::startsWith);
     }
 
 }
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/game/Library.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/game/Library.java
index a8eeee2a3..b783e192f 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/game/Library.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/game/Library.java
@@ -22,6 +22,7 @@ import com.google.gson.reflect.TypeToken;
 import org.jackhuang.hmcl.util.Constants;
 import org.jackhuang.hmcl.util.OperatingSystem;
 import org.jackhuang.hmcl.util.Platform;
+import org.jackhuang.hmcl.util.ToStringBuilder;
 
 import java.lang.reflect.Type;
 import java.util.List;
@@ -142,7 +143,7 @@ public class Library implements Comparable<Library> {
 
     @Override
     public String toString() {
-        return "Library[" + getName() + "]";
+        return new ToStringBuilder(this).append("name", getName()).toString();
     }
 
     @Override
diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/util/ToStringBuilder.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/util/ToStringBuilder.java
new file mode 100644
index 000000000..29135510f
--- /dev/null
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/util/ToStringBuilder.java
@@ -0,0 +1,23 @@
+package org.jackhuang.hmcl.util;
+
+public class ToStringBuilder {
+
+    private final StringBuilder stringBuilder;
+    private boolean first = true;
+
+    public ToStringBuilder(Object object) {
+        stringBuilder = new StringBuilder(object.getClass().getSimpleName()).append(" [");
+    }
+
+    public ToStringBuilder append(String name, Object content) {
+        if (!first)
+            stringBuilder.append(", ");
+        stringBuilder.append(name).append('=').append(content.toString());
+        return this;
+    }
+
+    @Override
+    public String toString() {
+        return stringBuilder.toString() + "]";
+    }
+}