Whats Wrong with my code?

Error: ./com/example/BlogPost.java:29: error: for-each not applicable to expression type for (BlogPost authorName : mPost) { ^ required: array or java.lang.Iterable found: String ./com/example/BlogPostFixture.java:9: error: constructor BlogPost in class BlogPost cannot be applied to given types; new BlogPost("Alice", "TITLE", "BODY", "CATEGORY", new Date()), ^ required: String,String,String,String,Date,String found: String,String,String,String,Date reason: actual and formal argument lists differ in length ./com/example/BlogPostFixture.java:10: error: constructor BlogPost in class BlogPost cannot be applied to given types; new BlogPost("Bob", "TITLE", "BODY", "CATEGORY", new Date()), ^ required: String,String,String,String,Date,String found: String,String,String,String,Date reason: actual and formal argument lists differ in length ./com/example/BlogPostFixture.java:11: error: constructor BlogPost in class BlogPost cannot be applied to given types; new BlogPost("Charlie", "TITLE", "BODY", "CATEGORY", new Date()), ^ required: String,String,String,String,Date,String found: String,String,String,String,Date reason: actual and formal argument lists differ in length ./com/example/BlogPostFixture.java:12: error: constructor BlogPost in class BlogPost cannot be applied to given types; new BlogPost("Alice", "TITLE", "BODY", "CATEGORY", new Date()), ^ required: String,String,String,String,Date,String found: String,String,String,String,Date reason: actual and formal argument lists differ in length ./com/example/BlogPostFixture.java:13: error: constructor BlogPost in class BlogPost cannot be applied to given types; new BlogPost("Bob", "TITLE", "BODY", "CATEGORY", new Date()), ^ required: String,String,String,String,Date,String found: String,String,String,String,Date reason: actual and formal argument lists differ in length ./com/example/BlogPostFixture.java:14: error: constructor BlogPost in class BlogPost cannot be applied to given types; new BlogPost("Charlie", "TITLE", "BODY", "CATEGORY", new Date()), ^ required: String,String,String,String,Date,String found: String,String,String,String,Date reason: actual and formal argument lists differ in length ./com/example/BlogPostFixture.java:15: error: constructor BlogPost in class BlogPost cannot be applied to given types; new BlogPost("Dave", "TITLE", "BODY", "CATEGORY", new Date()), ^ required: String,String,String,String,Date,String found: String,String,String,String,Date reason: actual and formal argument lists differ in length ./com/example/BlogPostFixture.java:16: error: constructor BlogPost in class BlogPost cannot be applied to given types; new BlogPost("Ephram", "TITLE", "BODY", "CATEGORY", new Date()), ^ required: String,String,String,String,Date,String found: String,String,String,String,Date reason: actual and formal argument lists differ in length ./com/example/BlogPostFixture.java:17: error: constructor BlogPost in class BlogPost cannot be applied to given types; new BlogPost("Alice", "TITLE", "BODY", "CATEGORY", new Date()), ^ required: String,String,String,String,Date,String found: String,String,String,String,Date reason: actual and formal argument lists differ in length ./com/example/BlogPostFixture.java:18: error: constructor BlogPost in class BlogPost cannot be applied to given types; new BlogPost("Alice", "TITLE", "BODY", "CATEGORY", new Date()) ^ required: String,String,String,String,Date,String found: String,String,String,String,Date reason: actual and formal argument lists differ in length Note: JavaTester.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details. 11 errors

showing in for Loop mPost

package com.example;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;


public class BlogPost implements Comparable<BlogPost>, Serializable {
  private String mAuthor;
  private String mTitle;
  private String mBody;
  private String mCategory;
  private String mPost;
  private Date mCreationDate;

  public BlogPost(String author, String title, String body, String category, Date creationDate,String post) {
    mAuthor = author;
    mTitle = title;
    mBody = body;
    mCategory = category;
    mCreationDate = creationDate;
    mPost=post;
  }
    public Set<String> getAllAuthors() {
    Set <String> set = new TreeSet<>();
    for (BlogPost authorName : mPost) {
     set.add(authorName.getAuthor()); 
    }
    return set;
  }

  public int compareTo(BlogPost other) {
    if (equals(other)) {
      return 0;
    }
    return mCreationDate.compareTo(other.mCreationDate);
  }

  public String[] getWords() {
    return mBody.split("\\s+");
  }

  public List<String> getExternalLinks() {
    List<String> links = new ArrayList<String>();
    for (String word : getWords()) {
      if (word.startsWith("http")) {
        links.add(word);
      }
    }
    return links;
  }

  public String getAuthor() {
    return mAuthor;
  }

  public String getTitle() {
    return mTitle;
  }

  public String getBody() {
    return mBody;
  }

  public String getCategory() {
    return mCategory;
  }

  public Date getCreationDate() {
    return mCreationDate;
  }
}

package com.example;

import java.util.List;

public class Blog {
  List<BlogPost> mPosts;

  public Blog(List<BlogPost> posts) {
    mPosts = posts;
  }

  public List<BlogPost> getPosts() {
    return mPosts;
  }
}