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POhibernate ManyToMany Java List removal
 

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  1. POhibernate ManyToMany Java List removal
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    <p>I have something like this</p> <pre><code>@Entity public class A implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) @Basic(optional = false) private Long id; @Basic(optional = false) private String name; @ManyToMany private List&lt;B&gt; bList = new ArrayList&lt;&gt;(0); public A() { } public List&lt;B&gt; getbList() { return bList; } public void setbList(List&lt;B&gt; bList) { this.bList = bList; } public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } } </code></pre> <p>and </p> <pre><code>@Entity public class B implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) @Basic(optional = false) private Long id; @Basic(optional = false) private Integer number; @ManyToMany private List&lt;A&gt; aList = new ArrayList&lt;&gt;(0); public B() { } public List&lt;A&gt; getaList() { return aList; } public void setaList(List&lt;A&gt; bList) { this.aList = bList; } public Long getId() { return id; } public void setId(Long id) { this.id = id; } public Integer getNumber() { return number; } public void setNumber(Integer number) { this.number = number; } } </code></pre> <p>Also</p> <pre><code>public class C { public C() { } public boolean addAtoB(Session hibernate, A a, B b) throws HibernateException { a.getbList().add(b); b.getaList().add(a); hibernate.saveOrUpdate(a); hibernate.saveOrUpdate(b); A aa = (A) hibernate.get(A.class, a.getId()); B bb = (B) hibernate.get(B.class, b.getId()); if (aa.getbList().contains(b) &amp;&amp; bb.getaList().contains(b)) { return true; } return false; } public boolean removeAfromB(Session hibernate, A a, B b) throws HibernateException { a.getbList().remove(b); b.getaList().remove(a); hibernate.saveOrUpdate(a); hibernate.saveOrUpdate(b); A aa = (A) hibernate.get(A.class, a.getId()); B bb = (B) hibernate.get(B.class, b.getId()); if (!(aa.getbList().contains(b) &amp;&amp; bb.getaList().contains(b))) { return true; } return false; } public boolean addListOfAtoB(Session hibernate, List&lt;A&gt; a, B b) throws HibernateException { boolean test = false; for (int i = 0; i &lt; a.size(); i++) { A aa = a.get(i); addAtoB(hibernate, aa, b); } test = true; return test; } public boolean removeListOfAtoB(Session hibernate, List&lt;A&gt; a, B b) throws HibernateException { boolean test = false; for (int i = 0; i &lt; a.size(); i++) { A aa = a.get(i); removeAfromB(hibernate, aa, b); } test = true; return test; } public Integer halfOfB(Session hibernate, List&lt;B&gt; b) throws Exception { for (int i = 0; i &lt; b.size(); i++) { B bb = b.get(i); List&lt;A&gt; aa = bb.getaList(); if (aa.size() &lt;= 5) { return aa.size(); } else { Integer br = (Integer) hibernate.createCriteria(B.class) .setProjection(Projections.max("number")).uniqueResult() + 1; B bbb = new B(); bbb.setNumber(br); List&lt;A&gt; half = aa.subList(aa.size() / 2, aa.size()); //error removeListOfAtoB(hibernate, half, bb); addListOfAtoB(hibernate, half, bbb); halfOfB(hibernate, b); } } throw new Exception("error in halfOfB"); } } </code></pre> <p>halfOfB is a recursive method that halves list of names into new list until there the list has at least than 5 names from A under a number of B.</p> <p>Before anyone asks why not one to many, becouse I need both entities to have multiple aplication, so ManytoMany is the only option. </p> <p>All methods in junit are green execept test for halfOfB throws java.util.ConcurrentModificationException. According to <a href="http://javaadami.blogspot.com/2007/09/enhanced-for-loop-and.html" rel="nofollow">this</a> if I use indexed for no ConcurrentModificationException should be thrown. Also if i reverse order</p> <pre><code> addListOfAtoB(hibernate, half, bbb); removeListOfAtoB(hibernate, half, bb); </code></pre> <p>I still get same error Any ideas how to make this work?</p>
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    1. PO
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      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USnkvnkv
    1. USnkvnkv
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
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    1. COCould you post the stacktrace?
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      1. POhibernate ManyToMany Java List removal
      1. USLefteris Laskaridis
 

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