You removed Alliance Member api for some reason

src/main/java/io/github/adorableskullmaster/pw4j/IPoliticsAndWar.java

@@ -21,6 +21,8 @@ public interface IPoliticsAndWar {
 
   Alliance getAlliance(int allianceId) throws IOException;
 
+  AllianceMembers getAllianceMembers(int allianceId) throws IOException;
+
   Alliances getAlliances() throws IOException;
 
   NationMilitary getAllMilitaries() throws IOException;

src/main/java/io/github/adorableskullmaster/pw4j/PoliticsAndWar.java

@@ -61,6 +61,11 @@ public Alliance getAlliance(int allianceId) throws IOException {
     return (Alliance) execute(new AllianceQuery(allianceId, apiKeyPool.getNextApiKey()).build());
   }
 
+  @Override
+  public AllianceMembers getAllianceMembers(int allianceId) throws IOException {
+    return (AllianceMembers) execute(new AllianceMembersQuery(allianceId, apiKeyPool.getNextApiKey()).build());
+  }
+
   @Override
   public Alliances getAlliances() throws IOException {
     return (Alliances) execute(new AlliancesQuery(apiKeyPool.getNextApiKey()).build());

src/main/java/io/github/adorableskullmaster/pw4j/domains/AllianceMembers.java

@@ -0,0 +1,48 @@
+package io.github.adorableskullmaster.pw4j.domains;
+
+import com.google.gson.annotations.Expose;
+import com.google.gson.annotations.SerializedName;
+import io.github.adorableskullmaster.pw4j.domains.subdomains.AllianceMembersContainer;
+
+import java.util.List;
+import java.util.Objects;
+
+public class AllianceMembers extends Entity {
+
+    @SerializedName("success")
+    @Expose
+    private Boolean success;
+    @SerializedName("nations")
+    @Expose
+    private List<AllianceMembersContainer> nations = null;
+
+    public Boolean isSuccess() {
+        return success;
+    }
+
+    public List<AllianceMembersContainer> getNations() {
+        return nations;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        AllianceMembers that = (AllianceMembers) o;
+        return Objects.equals(success, that.success) &&
+                Objects.equals(nations, that.nations);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(success, nations);
+    }
+
+    @Override
+    public String toString() {
+        return "AllianceMembers{" +
+                "success=" + success +
+                ", nations=" + nations +
+                '}';
+    }
+}