Java Programming

Hello,

I'm using PDFBox trying to read (2) pdf files in it, but both are big in size(About 17 MB) each.
Here is an example for what i want to do :

public void loadPdfs() { 
   String pdf1FilePath = "c:\\java long pdf1.pdf"; 
   String pdf2FilePath = "c:\\java long pdf2.pdf"; 
 
   try { 
      PDDocument pdf1File = PDDocument.load( pdf1FilePath ); 
      //....Do some stuff here. 
      pdf1File.close(); 
      Runtime.getRuntime().gc(); 
      PDDocument pdf2File = PDDocument.load( pdf2FilePath ); //This line causes the Exception. 
   } catch (IOException e) { 
      e.printStackTrace(); 
   }  
} 

I get this Exception :

org.pdfbox.exceptions.WrappedIOException: Java heap space 
. 
. 
. 
java.lang.OutOfMemoryError: Java heap space 

And if i tried to load only (1) pdf it works fine. So why does this happen ?
I do close the first pdf, and run the Garbage Collector, so when opening the second pdf, it's as if opening (1) file now, or am i mistaken ?