ArrayList of ArrayLists - clear funcion confusion
<p>Here is a particular method I have written:  </p>

<pre><code>class A {

    private static ArrayList&lt;ArrayList&lt;Integer&gt;&gt; inputTerms = new ArrayList&lt;ArrayList&lt;Integer&gt;();

    public static void method1(ArrayList&lt;Integer&gt; terms) {
        ArrayList&lt;Integer&gt; clauses = new ArrayList&lt;Integer&gt;();
        int N = terms.size();
        for (int i = 0; i &lt; N - 1; i++) {
            for (int j = i + 1; j &lt; N; j++) {
                clauses.add(-terms.get(i));
                clauses.add(-terms.get(j));
                inputTerms.add(clauses);
                clauses.clear();
            }
        }
    }
}
</code></pre>

<p>This method is called multiple times from the main function.
In the end, i try to write the contents of the class variable into a file. However, when I do this, i get 0 as the contents of inputTerms. However, if i remove the clauses.clear() line, i am able to get approppriate values.</p>

<p>My program is such that it is vital for me to clear the clauses after adding to inputTerms. Is there any alternative to this?</p>

<p>**Hmmm.. I have done what you ve suggested. However, I havent quite overcome the problem. To give more background, in my main function, i have the following code: </p>

<pre><code>for (int i=0; i&lt;N-1; i++){ 
ArrayList&lt;Integer&gt; firstdiagonalTerms = new ArrayList&lt;Integer&gt;(); 
for (int j=0; j&lt;N-i; j++){ 
firstdiagonalTerms.add(variable[j][i+j]); 
} 
method1(firstdiagonalTerms);
} 
</code></pre>

<p>i have to call the method1 fuction 4 times for different combinations of 'i' and 'j'. However, i still get 0 when i use the above mentioned suggestions**</p>
