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Java Java Data Structures Exploring the Java Collection Framework ArrayLists

luke hammer
luke hammer
25,513 Points
Posted by luke hammer
luke hammer
25,513 Points

Java <String> and List problem

keep getting error ./com/example/BlogPost.java:34: error: cannot find symbol public List getExternalLinks(){ ^ symbol: class Strings location: class BlogPost Note: JavaTester.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details. 1 error

Please can some one explain what the error means and then what i can do to fix my code.

Thank you.

com/example/BlogPost.java 
package com.example;

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


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

  public BlogPost(String author, String title, String body, String category, Date creationDate) {
    mAuthor = author;
    mTitle = title;
    mBody = body;
    mCategory = category;
    mCreationDate = creationDate;
  }

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

  public String[] getWords() {
    return mBody.split("\\s+");
  }
  public List<Strings> getExternalLinks(){
    List<String> results = new ArrayList<String>();
    for (String word : getWords()) {
      if (word.startsWith("http")){
        results.add(word);
      }
    }  
      return results;  
  };


  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;
  }
}

1 Answer

miguelcastro2
miguelcastro2
Courses Plus Student 6,573 Points

Should be "String", not "Strings":

// Should be a List of type String, not Strings
 public List<Strings> getExternalLinks(){

// Correct
 public List<String> getExternalLinks(){
luke hammer
luke hammer
25,513 Points
luke hammer
luke hammer
25,513 Points

your right and that was a problem but I'm still getting an error.

./com/example/BlogPost.java:33: error: cannot find symbol public List getExternalLinks(){ ^ symbol: class string location: class BlogPost Note: JavaTester.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details. 1 error

package com.example;

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

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

  public BlogPost(String author, String title, String body, String category, Date creationDate) {
    mAuthor = author;
    mTitle = title;
    mBody = body;
    mCategory = category;
    mCreationDate = creationDate;
  }

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



  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;
  }
}
luke hammer
luke hammer
25,513 Points
luke hammer
luke hammer
25,513 Points

Weird it did not work that first time but worked when i attempted to do it again.